Yamaha TRX850 Enthusiasts Forum

For some reason I had it in my head that 120/60/17 was the correct front tyre size, but Davamb tells me I'm wrong & 120/70 is the correct size

I think this stems from a set Conti tyres I got years ago that I got the shop to fit for me, I think they just sold me whatever they had in stock rather than getting the right ones in

Mind you I've not had any handling issues...

What are we all using?

They came out std with 120/60 on the front. With a pretty neutral steering this quickened things up just a little but you just have that feeling of the front end falling from under you when you drop into a corner.
I was running a 70 series on the front before the rebuild ,it was noticeable when I had Rod's bike to ride around on when I first started my rebuild as he had a 60 series and the first few corners i found myself putting my foot down till I got the feel of things again.
Running a 170 rear will raise the rear a couple of mm and the gearing a touch also . Things to keep in mind.
I've run 170 Dunlops and Michelins and found just a slight under steer out of the corners but can easily be worked around and still allows you to utilize the full rubber potential of the tyre width with no chicken strips as if you choose to go for a 180 which is the outer limit of tyre fittment on a 5" rim
The dunlop slicks I'm running do not come in a 60 profile so another erason to use 70 series on both road and track. Plus the added protection from dinging the rim with the 60 series

Metzeler 120/70 for the front and a 180/55 to the rear..
M5 sportec rubber.....but that's for the modified lads.

Dunlop qualifier II
120/70 - 180/55

Michelin pilot road 2 120/70 and Bridgestone 170/60 (R1 front ,standard rear)

Metzeler 120/70 m5 sportec interact.
Metzeler 180/55 m5 sportec Interact.

120/70 front and 170/60 rear..
Run with both standard and R1 front ends.

It is worthy to note though that stated size can differ from actual measured width by anything up to +/- 5%. Profile character will effect tyre handling much more than a given width, as you need to look at how the tyre will transition and the contact patch at a given lean angle plus stability. It's horses for courses in riding style and application.
From memory I have seen 170's measure anything from 163 to 176 and 160's from 156 to 168. Fronts at 120 tend to be a bit tighter to stated size, but I spent more attention researching rear fittings over the years.

A quick example:
Dunlop Sportsmart 160/60 is 168mm and diameter of 632mm
Dunlop Sportsmax Q2 160/60 is 171mm and diameter of 630mm
Dunlop Sportsmax Q2 170/60 is 165mm and diameter of 634mm

120/70 front and good old 160/60 rear because of this:
http://www.trx850.com/phpBB_forum/viewt ... f=6&t=4941

Those running 180's on the rear, is that a TRX rim or something else?

M.V. wrote:Those running 180's on the rear, is that a TRX rim or something else?

I've heard of some useing a180 on the trx 5inch rim, but it would be a 5.5inch rim that would have the 180 MV.
R1-R6-YZF750-VFR800 ect

So true on the profiles and width of tyres. One thing I was taking particular attention to on the bikes at the expo yesterday.
The weight of the tyres also is another point of interest.

http://www.motorcycle-usa.com/545/8285/ ... rison.aspx

M.V. wrote:Those running 180's on the rear, is that a TRX rim or something else?

YZF

Killerwhale wrote:

M.V. wrote:Those running 180's on the rear, is that a TRX rim or something else?

YZF

I ve run a 180 on the 5 inch and now the yzf 5.5. Made no difference on the ride or cornering. There was improvement moving from 160 to 180 though.

Tried the 120/60 but preferred the tip in of the 120/70. Just replace the 160 with a 170, not sure if I like it more or not. Does look a bit better in my opinion, that's got to be worth something

my bike came with a 120/60 front. had a tendency to tank-slap down hill on the overun if you lifted off the bars.

got new michelin pilot road 4s and went for the 70 ratio on the front ( standard 160/60 rear) but also put in new front wheel bearing as the old one felt slightly rough. Problem solved but I don't know which solved it bearing or tyre.

( tyres are great btw total confidence, no chicken strips on rear and I'm no Reuben Xaus. )