Tyre size, profile and rim size. Is bigger better?

**nzspokes** · 18th September 2011, 19:21

Ive got 18" rims. 215 x 18 rear and 185 x 18 front.

Ive got Sport Demons in 110 x 80 rear and 100 x 90 front. It looks a bit unbalanced.

As spares I have 1 x 110 x 90 rear sport demon and 1 x 90 x 90 MT75.

All tyres are in great condition. Should I fit the 110 x 90 on the bike to match the front?

Does profile make a big difference?

And the big question, does a wider rear tyre grip better or does it just weigh more and slow the bike down?

**James Deuce** · 18th September 2011, 19:40

You do whatever you want. You blindly disregard the knowledge and expertise of skilled engineers who design suspension systems for customers around the world, so I'm betting you know more than any damn tyre company.

**bogan** · 18th September 2011, 19:57

Here's one I prepared earlier

**nzspokes** · 18th September 2011, 20:14

Originally Posted by bogan

Here's one I prepared e.arlier

Cheers, interesting read.

Must remember to use search function.

I kinda want to put the smaller MT75 on the front but not sure how old/hard/any good it is. The sport demons feel good.

**FJRider** · 18th September 2011, 20:17

Originally Posted by nzspokes

Cheers, interesting read.

Must remember to use search function.

I kinda want to put the smaller MT75 on the front but not sure how old/hard/any good it is. The sport demons feel good.

Changing tyre profiles (on the front) may affect speedo accuracy ...

**bogan** · 18th September 2011, 20:22

So much tyre talk everywhere I would doubt the search would help.

Basically, the main thing you want, is to have profiles that work well together, different manufacturers have different profiles which don't show up in the figures. Mixing brands and sizes makes it harder to get that match, my guess is the mismatch will be most evident in turn in, and perhaps alter the force required on the bars during cornering. Dunno though, I run a matching pair

**nzspokes** · 18th September 2011, 20:25

Originally Posted by FJRider

Changing tyre profiles (on the front) may affect speedo accuracy ...

True. I use a back up bicycle speedo that is very easy to calibrate to any tyre size.

**nzspokes** · 18th September 2011, 20:26

Originally Posted by bogan

Dunno though, I run a matching pair

Which I want to as well. I may sell my spare tyres and buy an 80 profile front to match the rear.

**MikeD400** · 18th September 2011, 21:01

Originally Posted by James Deuce

You do whatever you want. You blindly disregard the knowledge and expertise of skilled engineers who design suspension systems for customers around the world, so I'm betting you know more than any damn tyre company.

Jerry! Jerry! Jerry!

Ps: Your foot note makes me lol.