Fatbike tyres what ...
 

Subscribe now and choose from over 30 free gifts worth up to £49 - Plus get £25 to spend in our shop

[Closed] Fatbike tyres what if...?

4 Posts
5 Users
0 Reactions
92 Views
Posts: 1012
Free Member
Topic starter
 

I got hold of some used jumbo Jim tyres for my sons on one trails...the original tyres are 4.0 JJ.....the 'new'ones are 4.8"....with a bit of trimming I can get these to fit the rear
What's the worst that could happen if i fit them?


 
Posted : 18/04/2022 9:06 am
Posts: 17984
Full Member
 

Fitting with the bike static is different to it fitting rolling, ime.

I had to take the 4.8 JJ off the rear of my Dune eventually as it rubbed the chainstay depending on pressure, depending on mud, depending on how much I thraped it down trails.

You might get away with it. Might not.

I've switched back to a 4 on the rear and have a 4.8 on the front.


 
Posted : 18/04/2022 9:14 am
Posts: 65983
Full Member
 

Yeah, fatbike tyres change shape a lot- when I put a Bud in the back of my Dune, it literally jammed solid in the frame at 15psi (tubeless-fitting pressure) but shrank so much at 6psi that it fitted with space to spare.

The 4.8 JJ is a much better tyre than the 4.0 imo, I'd never go back but in the end a tyre that doesn't fit isn't very good! I don't think I'd cut one to fit, if it doesn't fit without cutting then I doubt you'll get enough clearance that way.


 
Posted : 18/04/2022 1:10 pm
Posts: 43539
Full Member
 

How much clearance is there between the chain and tyre when in the innermost sprocket(s)?


 
Posted : 18/04/2022 1:22 pm
Posts: 0
Free Member
 

You could go for a 4.4 on the rear


 
Posted : 19/04/2022 2:13 pm