Hitchcocks Forum

Hello everyone, I was wondering if I could or if anyone else has fitted the Avon Roadrider 100/90/19 on the front. This is a reversible tyre but I want to know if there are any clearance issues that I might face if I put it on the front. I'm definitely going to fit this tyre (100/90/19) on the rear but just wanted to know if I should stick to the stock 90/90/19 for the front? Bike is a 2016 royal enfield Bullet B5. Also side note, the website selling the tyres shows both 90/90/19 and 3.25/19, I'm assuming they are the same? I'm located in Canada, the link to the website is here: https://fortnine.ca/en/avon-am26-roadrider-front-tire , if you scroll down you can see the fitment guide of which tyres are reversible are other things such as sizing, speed rating, ETC.

90/90-19 and 3.25-19 are similar but slightly different tyre sizes.



The 3.25 is the nominal width in inches. The first 90 is the nominal width in mm, the second 90 is the percentage of that width making up the profile height. If the width is given in inches, it's usually a 100% profile.



As with all things motorcycle. It's not as simple as all that. In theory, a 90 width should be 3.5" across. In fact, a 90/90 roadrider is 3.9" wide and a 3.25 is 3.8" wide. Which goes to show you never can tell and it's best to consult the manufacturers specs (which is I what I did).



Short answer. Both will fit your bike. The 3.25-19 will have a marginally higher profile and therefore around 1" larger rolling diameter as compared to the 90/90 It would will land up 1/2" closer to the mudguard and will appear more perfectly circular in cross section rather than oval (this will tend to make it a little more responsive to turning forces but with a marginally smaller contact patch). The width is so close as to make very little difference. Both have a V speed rating.



Just something else you may not be aware of. It's not 90/90/19. It's 90/90-19. The hyphen denotes a bias belt tyre. If it was 90/90 19 it would be a cross ply and if it was 90/90 R19 it would be radial. Relevant because if you have a bias belt or crossply on the front, it's illegal to fit a radial on the rear.



They are good tyres which will take much more than an enfield can throw at them. Even a tuned one. Personally, I'd fit the 90/90 for the slightly larger contact patch and more oval cross section, they are short bikes anyway, speed of turning in isn't usually an issue and the rake angle isn't so severe that it will be badly tightened by the 1/2" change in ride height.



TL;DR Sorry about the stream of conciousness there, I nerded out for a moment. Yes, either will fit a bullet because there is plenty of mudguard clearance. No, they are not the same but most people would notice little difference between the two. Get whichever is cheaper.

I should add. The mixing of bias belt/crossply and radial thing is the law in the UK. It may be different in Canada.

Thanks stinkwheel, the 90/90 it is. Very descriptive and helpful, have a good day.