2.5 Rear Rim Fitment?

[woody928]

Hi All,

If I'm having my wheels rebuilt and getting new rims at the same time, and I'm planning to go wider to accommodate more modern rubber.

I've got 3.25 - 19 and 4.0 - 18 Avon Roadrider Mk2 Tyres. Looking at Avon's websites I really want wider rims for better fitment.

I'm planning to go up to a 19 - 2.15 rim up front, and would like to go up to a 18 - 2.5 on the rear. Will the rear wheel clear the frame and chain etc at 2.5? I think it will but would love some confirmation before pulling the trigger. 

Many thanks in advance

[Trigger]

For a 3.25 tyre, you would require a 1.85 rim which can take up to a 3.50 tyre. And for a 4.00 tyre you will require a 2.15 rim. The clearance problem is not the frame its, the torsion bar 

[woody928]

For a 3.25 tyre, you would require a 1.85 rim which can take up to a 3.50 tyre. And for a 4.00 tyre you will require a 2.15 rim. The clearance problem is not the frame its, the torsion bar 

Looking at Avons website for these tyres it’s suggesting bigger rims, seeing as I’m going custom anyway would it not be advisable to follow the manufacturers specs?

Assuming the above quoted sizes would fit that is? I know that combo your quoting would work on the minimum reccomended widths but I thought I should go for the optimum setup given the choice, no?

Would I run into issues with a 2.5 rear rim?

https://www.avontyres.com/en-gb/tyres/roadrider-mkii?cartype=motorcycle

[Trigger]

Can not see any mention on fitments to any SOHC's on the Avon site 
 With 2.15 rim and a 4.00 tyre, you only have a 10 to 15mm clearance between the tyre wall and the torsion bar. Any wider on the rim the tyre wall will be wider when inflated 

[Johnwebley]

I doubt the mods will improve the handling.

Sent from my SM-A750FN using Tapatalk

[Trigger]

I doubt the mods will improve the handling.

Sent from my SM-A750FN using Tapatalk

As us Ex racers know John, It is down to the surface, how skillful the rider is and wider rims don't make any difference whatsoever 

[woody928]

Can not see any mention on fitments to any SOHC's on the Avon site 
 With 2.15 rim and a 4.00 tyre, you only have a 10 to 15mm clearance between the tyre wall and the torsion bar. Any wider on the rim the tyre wall will be wider when inflated 

Point well made, I’m here to listen to the pros.

Would there be any benefit or fitment issues with going 2.15 on the front?

It sounds like it’s prudent and sensible to stick to 2.15 on the rear from all of your comments. I was just looking for the most suitable rim for the tyres given the opportunity to change them and also thought aesthetically they’d fill the rear a little more. From what you’d said, it’s a certain that there would be rubbing issues...

[woody928]

I doubt the mods will improve the handling.

Sent from my SM-A750FN using Tapatalk

As us Ex racers know John, It is down to the surface, how skillful the rider is and wider rims don't make any difference whatsoever 

Haha I have no doubt, I just wanted to make the most of the opportunity while I’m starting again from scratch. Ultimately I want the bike to handle correctly first however if I can improve on the aesthetics then why not....

[woody928]

I found the handling to be perfect with 2.15 rims front and rear, it stops rim creep on the tyre when using wider tyres than standard.

Thanks for the input Ken, that's good to know 

[woody928]

Just to close this off and update you all, I've requested the following size rims be built for my 550 with my Avon Roadriders:

19 - 1.85 Front
18 - 2.15 Rear

I decided that I didn't want any fitment issues and am ultimately building the bike with performance in mind. I've spent hours wasting time researching wider rims looking at what may be best. The only last temptation was to go to a  2.15 on the front but I don't get the impression that it gains me anything...

Thanks for the wisdom.