27.5" with 26" wheels

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27.5" with 26" wheels
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Posted: Jan 28, 2020 at 20:58 Quote
Has anyone ever tried running a 27.5" front fork & wheel with a 26" rear wheel and frame? Im having a hard time finding a 26" fork for my bike. Thinking of getting 27.5 complete set up in front.
All dirtbikes Motorcycles have 21" front and 18" back. Seems ok to me?

Posted: Jan 28, 2020 at 21:58 Quote
Motorcycles are designed around the different wheel sizes; they're not added after the fact. There's nothing wrong with having different wheel sizes - even adding them after the fact - but it will change the handling of the bike. Maybe you won't like the change. Maybe you'll like it better.

If you use the same stroke (travel), the front end will be about 30 mm higher. You could use a bit less stroke and reduce the static (unweighted) difference, but the difference at bottom-out will always be about 30 mm.

• Your head-tube angle will get slacker. Steering will be a bit more stable / less agile at high speed and tracking will be a bit worse at low speed.
• Your seat-tube angle will get a bit a slacker. Your weight will shift rearward, which will probably be annoying on climbs. You can move your seat forward to compensate, which will make the bike feel shorter.
• The bike will roll over things with a bit less hang-up. You'll probably like this. Minor difference, though.
• It will be easier to find nice tires for the front wheel, but you won't be able to maximize tire life by moving a halfway worn tire to the rear and getting a fresh front.

Not wrong, just different.

Posted: Jan 29, 2020 at 0:07 Quote
Thanks for the feed back. Its a old bike anyway. 2006 Specialized Enduro with 36 Fox Talas forks with 20mm axle. Very hard to find the right fork that will fit my frame and wheel hub. I'm sure it will be my spare bike. I'll probably just pick up a 27.5 fork & wheel. Travel probably be less. I thinking the stance will be very close to the same.
R-M-R wrote:
Motorcycles are designed around the different wheel sizes; they're not added after the fact. There's nothing wrong with having different wheel sizes - even adding them after the fact - but it will change the handling of the bike. Maybe you won't like the change. Maybe you'll like it better.

If you use the same stroke (travel), the front end will be about 30 mm higher. You could use a bit less stroke and reduce the static (unweighted) difference, but the difference at bottom-out will always be about 30 mm.

• Your head-tube angle will get slacker. Steering will be a bit more stable / less agile at high speed and tracking will be a bit worse at low speed.
• Your seat-tube angle will get a bit a slacker. Your weight will shift rearward, which will probably be annoying on climbs. You can move your seat forward to compensate, which will make the bike feel shorter.
• The bike will roll over things with a bit less hang-up. You'll probably like this. Minor difference, though.
• It will be easier to find nice tires for the front wheel, but you won't be able to maximize tire life by moving a halfway worn tire to the rear and getting a fresh front.

Not wrong, just different.

Posted: Jan 29, 2020 at 0:45 Quote
Static geometry may be similar, but it will be slacker at bottom-out. Might improve the handling.

Posted: Jan 29, 2020 at 1:06 Quote
I was planning on putting a 26 wheel on the back of my 27.5 trail bike. Think it'll make it lower and slacker which is great for downhill but obviously will have it's drawbacks.

Posted: Jan 29, 2020 at 1:40 Quote
T4THH wrote:
I was planning on putting a 26 wheel on the back of my 27.5 trail bike. Think it'll make it lower and slacker which is great for downhill but obviously will have it's drawbacks.

BB height, mostly. You can reduce crank strikes via:

• Shorter cranks
• Less sag
• Firmer low-speed compression damping

Posted: Jan 29, 2020 at 5:56 Quote
R-M-R wrote:

BB height, mostly. You can reduce crank strikes via:

• Shorter cranks
• Less sag
• Firmer low-speed compression damping

That helps a lot, thanks

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