Will a 2018 seat fit a 2023 C400GT?

[emjoa]

I want to try reshaping the plastic seat pan and having it reupholstered so I can hopefully sit far enough back to accommodate my arthritic knee (last ditch effort before having to sell the bike) but am worried about restoring the seat to stock if it doesn't work out. I found a factory second seat on ebay for a fraction of what it would cost to order a new one from BMW, but it's for a 2018 model. It looks exactly the same as my 2023 C400GT seat in the photos, but before I pull the trigger I just thought I'd ask here if anyone knows if the seats are identical across the years for this bike. Anyone have any experience with this?

 

[mjnorris]

I want to try reshaping the plastic seat pan and having it reupholstered so I can hopefully sit far enough back to accommodate my arthritic knee (last ditch effort before having to sell the bike) but am worried about restoring the seat to stock if it doesn't work out. I found a factory second seat on ebay for a fraction of what it would cost to order a new one from BMW, but it's for a 2018 model. It looks exactly the same as my 2023 C400GT seat in the photos, but before I pull the trigger I just thought I'd ask here if anyone knows if the seats are identical across the years for this bike. Anyone have any experience with this?

Ask your dealership if the part numbers are the same for both bikes.

 

[emjoa]

Ask your dealership if the part numbers are the same for both bikes.

Thanks, not sure why I didn't think of that but that's a good idea!

 

[wspollack]

I want to try reshaping the plastic seat pan and having it reupholstered so I can hopefully sit far enough back to accommodate my arthritic knee (last ditch effort before having to sell the bike) but am worried about restoring the seat to stock if it doesn't work out. I found a factory second seat on ebay for a fraction of what it would cost to order a new one from BMW, but it's for a 2018 model. It looks exactly the same as my 2023 C400GT seat in the photos, but before I pull the trigger I just thought I'd ask here if anyone knows if the seats are identical across the years for this bike. Anyone have any experience with this?

It looks to me as if the seats on the '18 and '23 C 400 GT are the same.

I'm looking at https://shop.maxbmw.com/fiche/DiagramsMain.aspx?vid=60292&rnd=09082020 (04/18-10/20) (about two-thirds down the page) ...

and ...

https://shop.maxbmw.com/fiche/DiagramsMain.aspx?vid=62062&rnd=10232024 (04/20-05/24) (about two-thirds down the page).

Both list, as the final superseding part numbers, 52535A70A16 for non-heated C 400 GT seats and 52535A70A82 for heated seats:





You may also be interested in this thread from August 2023:

M

Thread 'Seat Mod From Advrider'

Aug 19, 2023

BMW C400X / C400GT

Tell me more about the bikes shortcomings. I'm interested. Stock suspension is probably the biggest one. It's ass. For me, the front suspension needs...

www.advrider.com

An owner posted this easy project over on advrider.com. Seems like a really good mod to at least try out if you are looking for a little extra space.

BMW C400X / C400GT

Tell me more about the bikes shortcomings. I'm interested. Stock suspension is probably the biggest one. It's ass. For me, the front suspension needs...

www.advrider.com

• mzflorida
• Replies: 11
• Forum: C400X - C400GT Modifications

• 

I own a '23 C 400 GT, but I prefer the C 400 X seat, which I've sat on through three Edelweiss tours now. While some folks might prefer the lower lumbar support afforded by the rider's portion of the GT's seat, I prefer the X's seat: it doesn't have that lower-back support, so instead provides more room to slide back and forth. (I am not interested in seat heating, because: 1) I sit atop BeadRider beads, anyway, and; 2) if it's cold out, I'll be wearing overpants and thermal long-johns.)

Good luck on your quest.

 

[emjoa]

It looks to me as if the seats on the '18 and '23 C 400 GT are the same.

I'm looking at https://shop.maxbmw.com/fiche/DiagramsMain.aspx?vid=60292&rnd=09082020 (04/18-10/20) (about two-thirds down the page) ...

and ...

https://shop.maxbmw.com/fiche/DiagramsMain.aspx?vid=62062&rnd=10232024 (04/20-05/24) (about two-thirds down the page).

Both list, as the final superseding part numbers, 52535A70A16 for non-heated C 400 GT seats and 52535A70A82 for heated seats:

View attachment 5698

View attachment 5699

You may also be interested in this thread from August 2023:

M

Thread 'Seat Mod From Advrider'

Aug 19, 2023

BMW C400X / C400GT

Tell me more about the bikes shortcomings. I'm interested. Stock suspension is probably the biggest one. It's ass. For me, the front suspension needs...

www.advrider.com

An owner posted this easy project over on advrider.com. Seems like a really good mod to at least try out if you are looking for a little extra space.

BMW C400X / C400GT

Tell me more about the bikes shortcomings. I'm interested. Stock suspension is probably the biggest one. It's ass. For me, the front suspension needs...

www.advrider.com

• mzflorida
• Replies: 11
• Forum: C400X - C400GT Modifications

• 

I own a '23 C 400 GT, but I prefer the C 400 X seat, which I've sat on through three Edelweiss tours now. While some folks might prefer the lower lumbar support afforded by the rider's portion of the GT's seat, I prefer the X's seat: it doesn't have that lower-back support, so instead provides more room to slide back and forth. (I am not interested in seat heating, because: 1) I sit atop BeadRider beads, anyway, and; 2) if it's cold out, I'll be wearing overpants and thermal long-johns.)

Good luck on your quest.

Thanks for that info Bill, much appreciated. I had asked my dealer for the part number to replace my seat and it didn't match what I saw on the one on ebay, but this seems to indicate that they are the same fitment regardless. I might just pull the trigger on the one I see on ebay, BUT...

Now that you mention you can sit farther back on the C400X seat I might just go that route, and I have more questions for you, if you don't mind.

First I just want to confirm that I understand you correctly, and that you are saying that the seat for a C400X will fit the C400GT. I'm not sure if you're saying you switched to a C400X entirely, or if you mounted the C400X seat on your GT. If it's the latter I think that might be my solution (I'm not all that concerned with loosing the seat heating if the X seat doesn't have it either. I also ride in all weather and regularly use long underwear and overpants as well on my current bike.) If you're saying that the C400X seat will fit the C400GT and that they are interchangeable I may want to give that a try so if you could confirm that's what you've done I'd appreciate it.

I also wanted to ask how far back you can sit on the C400X seat. I've seen pictures of it and had already considered trying this, but it looks like it also has a hump in the seat and that the pillion is as high on that as it is on the GT seat once the lumbar support has been removed on the latter. (I've already removed the lumbar support on my GT seat but it doesn't allow me to move far enough back to actually straighten my leg, which is what I need.) None of the dealerships around me sell the C400X or I would just go sit on one to test it out, and all I can go on are a few pictures I've seen on the net, but it looks like that hump will still keep me from moving back the 6 or so inches that I think I need. Is this just a case of the look/styling in the photos, and can a person really sit back that much farther on the X seat in your real world experience? I'd love to get more information about that...

I own a Honda PCX 150 and the original seat caused me the same problem. It doesn't have a big lumbar support like the C400GT, but just the hump between rider and pillion positions was enough to keep me from sliding my butt back the extra few inches I needed to straighten my leg. I was able to order an aftermarket seat from Thailand for my Honda that has a flatter seat pan itself, and while it still has a slope, I'm able to move back as far as I want to on it and have been riding that for years with no problems. I remember seeing pictures of that aftermarket seat and worrying that it still had too much of a hump, but upon receiving and mounting it I found I could slide back to any position I want, and I'm actually sitting half way on the pillion on that bike. based on what you just said, I'm wondering if this is a similar situation between the GT and X seats and that it looks like more of a restrictive hump in pictures of the X seat than it is in reality.

How far back can you actually move on the X seat? I have a 34" inseam and am hoping to be able to move back far enough to almost straighten my legs (I can keep my knee bent a bit, maybe 10 or 15 degrees, but not much more than that it seems) while at the same time still being able to reach the ground comfortabely enough. Based on your height/inseam length, and your experience with the X seat on the GT bike, would you say this is possible? Or is it more like it affords you an extra inch or two but that the hump before the pillion would keep you from sliding further back?

I suppose I could just take my chances and order a C400X seat to try it out, but that's an expensive proposition where I am and from what I have seen I wouldn't be able to return the seat and get my money back if it doesn't fit my bike or fit my legs... Hoping you could answer the above and share a bit more of your experience with your setup. As mentioned, if I could solve this issue it would allow me to keep the bike, but if I can't I'll most likely have to sell it without ever getting to really use it...

Thanks,
Mike

 

[wspollack]

First I just want to confirm that I understand you correctly, and that you are saying that the seat for a C400X will fit the C400GT. I'm not sure if you're saying you switched to a C400X entirely, or if you mounted the C400X seat on your GT. If it's the latter I think that might be my solution (I'm not all that concerned with loosing the seat heating if the X seat doesn't have it either. I also ride in all weather and regularly use long underwear and overpants as well on my current bike.) If you're saying that the C400X seat will fit the C400GT and that they are interchangeable I may want to give that a try so if you could confirm that's what you've done I'd appreciate it.

First, thanks for the kind words.

Second: no no no! No, I have NOT replaced my C 400 GT with a C 400 X seat. I don't know that such a swap will work -- I'm guessing that it will work, but that's only a guess.

I rode on a C 400 X bike for two five-day (2022) and one nine-day Edelweiss tours (2023), so that's my experience with a C 400 X and its stock seat. I preferred it to the stock seats on my former '22 and current '23 C 400 GT, but I don't want to risk all the money involved in an actual experiment, i.e., to see whether the X seat would really fit a GT.

The part numbers are obviously different for the X and GT variants, given that the former has no butt stop. But the Storage Compartment -- the underseat "washtub" -- part numbers are the same (both superseding to 46545A89731), which is why I'm guessing that the seats that go on top of them would be interchangeable.

I hope this clarifies the situation a little better. My apologies for not being clearer.

 

[emjoa]

First, thanks for the kind words.

Second: no no no! No, I have NOT replaced my C 400 GT with a C 400 X seat. I don't know that such a swap will work -- I'm guessing that it will work, but that's only a guess.

I rode on a C 400 X bike for two five-day (2022) and one nine-day Edelweiss tours (2023), so that's my experience with a C 400 X and its stock seat. I preferred it to the stock seats on my former '22 and current '23 C 400 GT, but I don't want to risk all the money involved in an actual experiment, i.e., to see whether the X seat would really fit a GT.

The part numbers are obviously different for the X and GT variants, given that the former has no butt stop. But the Storage Compartment -- the underseat "washtub" -- part numbers are the same (both superseding to 46545A89731), which is why I'm guessing that the seats that go on top of them would be interchangeable.

I hope this clarifies the situation a little better. My apologies for not being clearer.

Ah, that is what I was thinking might be the case. Thanks very much for clarifying what you meant. I think I'll stick to getting that cheap GT seat I saw on ebay (the seller has agreed to an even cheaper price for me) and will take my chances at having it reshaped and then reupholstered. I found a metal fabricator locally who thinks we could cut part of the seat pan out and then replace it with some aluminum so I could actually sit farther back, so I think I'll give that a try. Being able to get a spare seat to experiment on for fairly cheap makes it at least worth trying I think...

Thanks again for the info and for sharing your experience. Much appreciated.

Mike

 

[Harry Hippy]

I have a brand new C400X seat in my garage.
Happy to take some pictures and measurements of the base if it’s any help.

 

[wspollack]

Ah, that is what I was thinking might be the case. Thanks very much for clarifying what you meant. I think I'll stick to getting that cheap GT seat I saw on ebay (the seller has agreed to an even cheaper price for me) and will take my chances at having it reshaped and then reupholstered. I found a metal fabricator locally who thinks we could cut part of the seat pan out and then replace it with some aluminum so I could actually sit farther back, so I think I'll give that a try. Being able to get a spare seat to experiment on for fairly cheap makes it at least worth trying I think...

Thanks again for the info and for sharing your experience. Much appreciated.

Mike

I think with your 34" inseam you're on the right track with a local fabricator, and then maybe a local upholsterer.

(I used a local upholsterer myself, about 15 years ago. I had him create a wrap-around topcase backrest for my wife, when I had my first Burgman 650 scooter.)

I'm 5'8" - 5'9" with a 29" - 30" inseam (I've been shrinking a bit, as I get well into geezerdom). Here's a pic (from 2023) of me, on a C 400 X, to perhaps help gauge how much stretch-out room I have:



Here's a pic from 2022, unfortunately not with my feet up, but these are the best I can do:



So it looks to me that if my legs were four or five inches longer I would not be able to fully straighten them, even sitting at the back of a C 400 X. (I'm assuming that the floorboard ergonomics of the X and the GT are the same.)

Good luck with your project.

 

[emjoa]

I think with your 34" inseam you're on the right track with a local fabricator, and then maybe a local upholsterer.

(I used a local upholsterer myself, about 15 years ago. I had him create a wrap-around topcase backrest for my wife, when I had my first Burgman 650 scooter.)

I'm 5'8" - 5'9" with a 29" - 30" inseam (I've been shrinking a bit, as I get well into geezerdom). Here's a pic (from 2023) of me, on a C 400 X, to perhaps help gauge how much stretch-out room I have:

View attachment 5700

Here's a pic from 2022, unfortunately not with my feet up, but these are the best I can do:

View attachment 5701

So it looks to me that if my legs were four or five inches longer I would not be able to fully straighten them, even sitting at the back of a C 400 X. (I'm assuming that the floorboard ergonomics of the X and the GT are the same.)

Good luck with your project.

Thanks again Bill, I really appreciate you providing what info you can. As you must imagine, finally upgrading to the kind of bike I've always wanted and then not being able to ride it is pretty frustrating.

These pics and the info you've provided re your height and inseam length tell me I'm probably better off just trying to mod the GT seat itself. It looks like the X seat has less of a butt-stop, but it's still prominent enough that I'd have to look at the same kind of modifications anyway.

I've just pulled the trigger on the spare seat I saw on ebay and all in with shipping it was only 1/4 of what it would have cost me to replace new. (And this one is new, it just has a defect in the stitching so it's essentially a factory second. Seeing as I'm planning on reupholstering it anyway that little hole in the stitching is of no concern.) At least now I'll have something I can cut up and experiment with to see if I can make something workable before I give up on riding this bike altogether. So far I've only been able to put about 800 miles on it and currently have it in storage while I wait for my knee to get better again. In the meantime I'll see if I can make a workable mod to the seat that will let me keep and enjoy this bike!

Thanks again for the info and suggestions, greatly appreciated!

 

[emjoa]

I have a brand new C400X seat in my garage.
Happy to take some pictures and measurements of the base if it’s any help.

Thanks very much for this! Very nice of you to offer to take the trouble. I've just purchased a spare GT seat that I can attempt to modify without altering the stock seat in case I have to just sell my GT so I don't think I'll need it. One thing I am curious about though is the shape of the X's seat pan. If you were willing to just snap a couple pics of the underside of your seat from a couple of different angles I could try to determine if the seat pan itself is flatter than that of the GT, and therefore more likely to work just by reupholstering. If the X's storage compartment is the same part as the GT I'm assuming the seats are interchangeable, so if my attempts to modify a GT seat fail I might look at trying to find an X seat for future reference...

Cheers,
Mike

 

[emjoa]

I have a brand new C400X seat in my garage.
Happy to take some pictures and measurements of the base if it’s any help.

Actually I found a couple of X seats on ebay as well with detailed pics and I can see that the pan itself has essentially (if not exactly) the same shape under the upholstery so no need to take pics and post them here. But thanks very much for the offer!

 

[Reguam]

I want to try reshaping the plastic seat pan and having it reupholstered so I can hopefully sit far enough back to accommodate my arthritic knee (last ditch effort before having to sell the bike) but am worried about restoring the seat to stock if it doesn't work out. I found a factory second seat on ebay for a fraction of what it would cost to order a new one from BMW, but it's for a 2018 model. It looks exactly the same as my 2023 C400GT seat in the photos, but before I pull the trigger I just thought I'd ask here if anyone knows if the seats are identical across the years for this bike. Anyone have any experience with this?

Have you tried removing the lumbar support and covering the hole and using an AirHawk cushion, which is also an enhancement. The back part of the AirHawk covers the bulky middle piece that holds the lumbar support pad. This give you much more space. If you still need back support add a Utopia backrest which in my opinion looks better without the factory lumbar. Notice this lumbar support was avoided on the X, and I think only used on the GT to cover a hard piece of plastic that you can feel through the seat.

 

[emjoa]

Have you tried removing the lumbar support and covering the hole and using an AirHawk cushion, which is also an enhancement. The back part of the AirHawk covers the bulky middle piece that holds the lumbar support pad. This give you much more space. If you still need back support add a Utopia backrest which in my opinion looks better without the factory lumbar. Notice this lumbar support was avoided on the X, and I think only used on the GT to cover a hard piece of plastic that you can feel through the seat.

Thanks Reguam, unfortunately I've already removed that lumbar support and while it did allow me some extra room it's just not enough straighten my extra long legs enough, but I'm going to try to modify the seat pan and then have it reupholstered so I can sit a good few inches back (might lose the ability to store a full face helmet but I'm willing to accept that trade off if it means I can actually ride the bike). Hopefully I can make it work I appreciate the input though, thanks for taking the time to write. Cheers!

 

[Reguam]

Thanks Reguam, unfortunately I've already removed that lumbar support and while it did allow me some extra room it's just not enough straighten my extra long legs enough, but I'm going to try to modify the seat pan and then have it reupholstered so I can sit a good few inches back (might lose the ability to store a full face helmet but I'm willing to accept that trade off if it means I can actually ride the bike). Hopefully I can make it work I appreciate the input though, thanks for taking the time to write. Cheers!

I feel your pain. Such a great bike with one big problem.

I have a helmet hook that goes on the end of the handle bar so the helmet space is available for storage. It has a hole to run a lock through. Especially useful when getting gas. Good luck. I will keep an eye on your posts.

My wife and I took our honeymoon from the Bay Area to Victoria forty years ago on a Honda CB900. Such a great ride up the coast into Canada. I would guess she has an additional 300K on the back of many bikes we have owned.

 

[emjoa]

I feel your pain. Such a great bike with one big problem.

I have a helmet hook that goes on the end of the handle bar so the helmet space is available for storage. It has a hole to run a lock through. Especially useful when getting gas. Good luck. I will keep an eye on your posts.

My wife and I took our honeymoon from the Bay Area to Victoria forty years ago on a Honda CB900. Such a great ride up the coast into Canada. I would guess she has an additional 300K on the back of many bikes we have owned.

I'm not going to give up on this bike yet, hopefully I can mod the seat and make it work. The small bike I'm riding now (Honda PCX 150) had a similar butt stop that created a similar problem but I was able to find an aftermarket flat seat for it and have been riding it for a few years without problem. Hopefully I can modify the seat pan for my C400 and get a similar result. I'll definitely report back here on my progress in case anyone else is interested. I know others have similar problems with their knees so if I'm successful it might be of use to others.

My PCX 150 has a metal hook attached to the frame just next to the lip of the storage area so you can hook your helmet's D ring on that and lock the seat, and it works a charm. I might also try adding something similar to the C400 if it works, but the handlebar hook you mentioned might also be an option to consider...

That sounds like it would have been a great trip. Victoria isn't quite the same quaint little town it was 40 years ago, but it's still a nice place to visit I'm sure (just not as nice to live here as it used to be). I'd love to do a similar trip in the opposite direction on day, last time I was in California I was 12 but I've always wanted to go back as an adult. So many beautiful places all up and down this coastline for sure.

I was hoping to do some road trips around Vancouver Island and the BC interior now that I have a scooter capable of highway speeds. I had already bought a 50L top box with that in mind. I have a niece that lives in the Okanagan Valley and a Nephew that lives in the Kootenays (Purcell mountain range, near the BC/Alberta border) so I have a couple of good destinations... Wish me luck with my seat mod and I might still be able to do that this summer.