Translating tire size

[derekgreen]

So I have a few questions. My bike is an 82 heritage special sj. Front tire is 3.00-18 and my rear is a 4/60 s16. I know that the rear translates to a 120/90 s16 but im not sure if the front is 90/90 18 or if I can use a 3.25-18 and have that fit properly with no rubbing. I am keeping the front fender off. So I wouldnt have to deal with any contact on that. I guess im wondering width wise. I found a set I can get that match and fit but they arent the type I was hoping for. But if they are what I gotta buy then oh well. Just curious about the 3.25-18 fitting.

Thanks for any advice.

 

[16VGTIDave]

3" is 76.2mm. There are precious few tires made below 90mm width these days. That's life.

A 3.25-18 tire should fit without any problems. It's only 1/4" wider overall than the stock tire, which results in an additional 1/8" width on either side of the tire. Not even worth mentioning. Unless your forks flex from not having a brace on them. Which they will do if you are not running the fender, and don't install a brace.

 

[xschris]

Lots of 90/90-18 (stock size) front tires out there still being made. Like dave said, no fender or fork brace will hurt handling.

 

[derekgreen]

I had my forks rebuilt with a bit stiffer springs. To be able to manage the handling issue that not running the fender will cause. If thats not enough ill figure out a brace. So I could go with a 90/90 or a 3.25 and not have any major issues.

 

[Wolfe_11B]

There is no replacement for a fork brace/stock fender. Stiffer springs might actually make the issue worse.

http://www.fastfromthepast.com/fork-braces/yamaha?limit=36

Well worth the $100. When I put mine on the old build you could feel the difference on the first corner at speed.

 

[derekgreen]

So if I got that I would go with the 25-0019? And it wouldnt cause any issues with fitting a slightly larger tire on the front?

 

[Wolfe_11B]

I think that would be correct, but you'll have to wait for a DOHC rider to be sure (or sohc? I'm not hip on the 82+ models and what is and isn't DOHC.) 25-0019 for DOHC 25-0017 for SOHC

Tarrozi designed them to clear the front fender, so I'm sure it can clear a wide range of tires.

 

[derekgreen]

My bike is sohc

 

[Wolfe_11B]

My bike is sohc

25-0017 it is then. The dust seals still fit over them too, a big plus.

You'll be fine with a bigger tire.

 

[derekgreen]

Fuck yeah. Lol thank you! Im gunna look in to a set of tires and that now.

 

[derekgreen]

Quick question. My tires are tubeless right? Want to be positive before I order my new set. 82 yamaha heritage special sj model. Sohc.

 

[Wolfe_11B]

Yes you should have the tubeless rims. If in doubt, it is marked 'tubeless' in the casting on one of the spokes

 

[derekgreen]

Im on the spoked wheels with the drum brakes.

 

[rshutchinson]

If you have cast wheels, you can run tubeless.

If they are spoked wheels like a bicycle then you need to run a tube and don't forget to get a rim band to protect the tube from the spoke ends.

 

[xschris]

Yes, 82 sj uses tubes. And it is alway a good idea to replace the rim band when ever replacing a tire.

 

[derekgreen]

So my front tire is tubbed and my rear tire isnt... should I just order a tube for the rear and go with that setup instead? I hear tubed is safer anyways as far as flats go. And they are the original rims so I know I could throw a tubless on the front if I wanted too. Thoughts?

 

[xschris]

If you have the stock spoked wheels they both should have tubes in them.

 

[derekgreen]

Thanks Chris. You just saved me a world of bs with shipping and returning lol.

 

[derekgreen]

Is there a trick I should know about the size gor tube ordering? Getting a tr-4 valve type for both wheels front tube is 2.75-19, 3.60-18 and the rear is 4.00-s16, 4.60-s16. They are the irc tubes off of bike bandit.

 

[rshutchinson]

You want 18" tube for the front, not sure if that was a typo or not. I used tr-6s. The rear tube is just under a 120 wheel, I would go up to the next size for the rear.