Yamaha TRX850 Enthusiasts Forum

Hi what size tyres should the trx have? Mine currently has a 120 on the front & a 180 on the rear but looking on eBay all the ads are for 160 on the rear? Also looking for recommendations I used to use Bridgestone but have been using Michelin for the last few years. Any help much appreciated ta.

I should point out I'm no longer a boy racer so looking for a good allround tyre something that grips but will have a certain amount of longevity cheers.

Hi benr!

For street use and improved stability while maintaining agility I recommend
120/70 at the front and
170/60 at the rear.
On standard rims of course.

Rubber rubbing greets from Munich!

I've had good success with the standard 120/60 and 160/60 though I've only recently realised the standard pressures of 36/42 seem to be too much - the book says 33/36, I'm currently running 35/38 with a Maxxis M6029 on the front and an Avon Storm Ultra 2 on the back. Keep the pressures a bit lower and it's way more flickable for some reason.

Also, with a 160/60 rear even I can get rid of all the chicken strips so you get to look like a hero

Thanks for the replies I thought a 180 was a bit big.

benr wrote:Thanks for the replies I thought a 180 was a bit big.

Yes, you were quite right. Stock is 160 and the TRX rear rim is 5" which is a too narrow spec for 180 even if it's possible to get it on there. 170 is recommended max.The TRX doesn't pump out all that much power however so there's no real reason to go beyond the standard 160 in the rear for any normal use. Most people do prefer 120/70 in the front instead of the rather silly 120/60 stock spec though.

Currently I'm running a set of Conti SportAttack 3s, 120/70 and 160/60. I use the bike pretty much every day for work, so I 'm more interested in wet grip and long life, rather than out and out performance. That said, they're good enough to scrape the pipes when I get carried away, so they can't be all that bad. I reckon I'll be going for the same tyres when these are due for renewal. I had a set of RaceAttack Comps previously, which had no end of grip, but didn't feel so good in the wet. Before that was a set of ex-race Pirelli something-or-others, and they were ****ing shocking. Wobbly in the dry, slippy in the wet, and about as much fun as a fart in a spacesuit. Threw them away well before they were worn out.

Stick to the recommended Tyre pressures from the tyre manufacturer.
They all have their own construction regime and some have stiffer carcasses and sidewalls than others so pressures will vary. Try to stick with matching front and rear for this exact same reason. They are designed to work in unison with each other.
If you choose to run a 70 series front tyre as most of us do, you have increased the profile height by 10% (12mm ) so you can accomodate by dropping the fork 12mm. Std they live 18mm through the forks anyhow so 30mm will get you back to std geometry.

nr wrote:Currently I'm running a set of Conti SportAttack 3s, 120/70 and 160/60. I use the bike pretty much every day for work, so I 'm more interested in wet grip and long life, rather than out and out performance. That said, they're good enough to scrape the pipes when I get carried away, so they can't be all that bad. I reckon I'll be going for the same tyres when these are due for renewal. I had a set of RaceAttack Comps previously, which had no end of grip, but didn't feel so good in the wet. Before that was a set of ex-race Pirelli something-or-others, and they were ****ing shocking. Wobbly in the dry, slippy in the wet, and about as much fun as a fart in a spacesuit. Threw them away well before they were worn out.

Interesting thanks. How many miles do you get out of those before changing?

cobbadiggabuddyblooo wrote:Stick to the recommended Tyre pressures from the tyre manufacturer.
They all have their own construction regime and some have stiffer carcasses and sidewalls than others so pressures will vary. Try to stick with matching front and rear for this exact same reason. They are designed to work in unison with each other.
If you choose to run a 70 series front tyre as most of us do, you have increased the profile height by 10% (12mm ) so you can accomodate by dropping the fork 12mm. Std they live 18mm through the forks anyhow so 30mm will get you back to std geometry.

Some sound advice there thanks. I usually tend to stick with a matching pair as you say it just works better.

Ditch the 160 front, it was a fad for a while in Japan but doesn't work as well as a 170.
Anything bigger than a 160 on the rear is a waste and will make the bike handle like a pig.
Pilot Sports are great if you ride the twisties a lot, Pilot Roads are nearly as good and last a lot longer.

jpe70 wrote:

benr wrote:Thanks for the replies I thought a 180 was a bit big.

Most people do prefer 120/70 in the front instead of the rather silly 120/60 stock spec though.

Highly recommend the 120/70 and having owned my TRX for many years, I've run both the 60 and the 70. With the 60 you'll run out of road fairly quickly (run wide), but the 70 will leave you with a "smile on your dial" and has the inbuilt margin should you ever really need to lay the bike over.

Michelins, Pilot Road 4 on the back and Pilot Power 3 on the front, give very even wear and a great level of grip
P.S I like Michelins but anything Black and Round with a good name will suit these bikes.

cobbadiggabuddyblooo wrote:Stick to the recommended Tyre pressures from the tyre manufacturer.
They all have their own construction regime and some have stiffer carcasses and sidewalls than others so pressures will vary. Try to stick with matching front and rear for this exact same reason. They are designed to work in unison with each other.
If you choose to run a 70 series front tyre as most of us do, you have increased the profile height by 10% (12mm ) so you can accomodate by dropping the fork 12mm. Std they live 18mm through the forks anyhow so 30mm will get you back to std geometry.

Just a query Brian, Is that 12mm radius or diameter


Michelin PR5, i'll let you know how they go.

Radius..
120mm width..and your heights are 60% or 70% of 120mm.
10% of 120mm=12mm extra height on the tyre wall..
The speedo drive is calibrated correctly for the 70 series too as with a 60 series 100kph on the speedo was actually 94-95kph ...

Lowering the forks in the yokes the 12mm with the 70 series front tyre is needed to stop the lazier turn due to the increase in rake with a higher tyre wall height.
Once the fork height compensation is made, the front end will feel much more linear when leaning into a corner and take away that sudden dropping in feel you have on the front end with the 60 series front tyre.
The 60 series tyre deacreases the steering rake at a lot faster rate than the 70 series tyre the more you lean into the corner.
You’ll feel what I mean if you run a 70 series...

As for the rear tyre...
160 is more than adequate on the std rear rim even with a trx running an extra 10hp.
Your limited with manufacturers who produce 170/60 and as Dicky mentioned , you need to make geometry changes to get it to work correctly too to stop it understeering/running wide out of corners..
That’s another kettle of fish... with rear ride height...

aah huh, I feel enlightened now I couldn't resist