Author Topic: R reg XS500 help with Tyres  (Read 2999 times)

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Offline response

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R reg XS500 help with Tyres
« on: December 10, 2014, 06:43:31 PM »
Hi guys. I am new this forum, but was hoping someone could help me.

I am doing a cafe racer from an XS500, it has aluminum rims, what is the widest tyres i can fit...? I am after the big Tyre look.

I am not sure what size rims i have, as the bike was a basket case... with no tyres fitted..



Offline mvluv13

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Re: R reg XS500 help with Tyres
« Reply #1 on: December 12, 2014, 03:24:12 AM »
Have a look on the inner side of the rim, should be stamped in there. More than likely rear 2.15-18 front 1.6-19.

Offline guylr

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Re: R reg XS500 help with Tyres
« Reply #2 on: December 12, 2014, 01:35:02 PM »
Front rims were 1.85-19.

The best 500 rims to use are from the 1978 XS500E because they are 2 pounds or so lighter due to the factory realizing that the original alloy rims were massively overbuilt out of caution. They trimmed the spokes to make them thinner. Crouchy is right that they are not rated as tubeless. That is due to the area below the bead sealing flange not being machined with a lip to retain the tire in case of a sudden deflation. The bead shape however is the same for both tube type and tubless rims. The other difference is at tube stem hole that is not specifically machined smooth to provide a seal for a tubeless stem. Nevertheless most rims are smooth enough to seal at that spot and many people do run tubeless tires without problems.

If you are interested in keeping the stock wheel look but want the lightest wheels available there are a couple of options. One is to use a late XS400 rear rim (2.15-18) which I believe in Europe may have also been tubeless. Running that rim tubeless and with an alloy rear sprocket will reduce the assembly weight by 4 pounds. if you also use an XS400 rear disc rotor (1L9) that is 2mm thinner your total savings will be about 5 pounds. That's how I run my XS500C and the difference in handling is very noticeable. i also made a conversion to 520 chain which helped even more so my setup is 6.6 pounds lighter when you factor in chain weight. 530 chain is way overkill for a 50hp bike.

You can also use the late SR500 rear wheel but that requires a few changes with the sprocket carrier and such that are probably not worth the trouble (except I may do it just to do it)

For the front wheel you can use a later XS850 or XS1100 front tubeless wheel. These are also 1.85-19 but are 10mm wider at the hub so that the disc rotors are too close to the fork sliders and you have to space the calipers out. The problem there is that the speedo drive unit doesn't fit right and has to be trimmed. So the fix there is to go on eBay and buy a fork underbracket and crown for an XS850 that spaces the forks 10mm wider apart. The 850 crown uses rubber dampers for the handlebar holders so make sure to buy a crown with those included.

The ultimate stock appearance wheel assemblies however are Japanese accessories for the original SR400/500. They are being reproduced using modern casting methods and are over 3 pounds pounds lighter per wheel than even the late tubeless wheels. Trouble is they are about $1300 US per set!

There are lots of mix and match parts swap options for our bikes in the late 70's/early 80's Yamaha models so feel free to ask questions on what will fit.


« Last Edit: December 12, 2014, 02:25:20 PM by guylr »
Now Retired Yamaha guy. Cut me and I bleed "Cinquasia Red"

Offline dean

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Re: R reg XS500 help with Tyres
« Reply #3 on: December 12, 2014, 06:01:01 PM »
what is the widest tyres i can fit...? I am after the big Tyre look

I thought I had posted this chart before. Our rims are not that wide, so if you want the tire to perform as designed don't go oversize. Oversize widths on modest rims really mess with the intended  tread sidewall relationship, handling etc.  If you really want that "big tyre look "  and don't care about safe handling or performance,  the widest tire is then what can physically fit between the forks or swing arm without hitting anything dangerous. 

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Re: R reg XS500 help with Tyres
« Reply #4 on: December 12, 2014, 08:40:09 PM »
Hi Guys. My tyre sizes are: FRONT 90 90 19.... rear is 120 90 18

Does this help?