120/70 instead of 120/60 front tyre

[twolfe]

I'm with Ridgi, I run a 170 rear. I didn't notice any difference between the 170 and the 160. I wonder how many people can actually tell the difference and how many think they can, because that is what they have been told or read.
Opinion has the 170 shagging the handling.... but apparently a 180 or 190 doesn't..... go figure

[phuk72]

It is nothing to do with the size of the tyre shagging the handling.

Using a 170 section will alter the handling characteristics. Not necessarily for the worse but you do need to bear in mind that you will have to alter all of your setting as you will, at the very least, increase the tyre height.

You may also find that using a larger tyre will require it to be 'squeezed' onto the rim and this will affect the profile of the tyre. This of course depends wholly on the make and manufacturer and tyre sizes differ wildly.

FWIW, my bike had brand new 170 on it when I bought it and I hated it. I noticed a big difference with a 160 section. Saying that, I also changed tyre brands so

Out of curiosity, what prompted the move to 170? Looks or tyre choice?

[burty]

I have the 70 profile front. Lowered the front yokes around 10 mm I think.

It works. The bike felt different. But the previous front was knackered also. I can't say whether I prefer it to the 60 profile TBH. But then I've not been on the track with it. I still find the TRX pretty confidence inspiring with either tyre TBH.

[twolfe]

I went with the 170 because that was all that was available at the time.I realise that fitting a bigger tyre on a small rim can cause odd shaped tyre profiles. My point was that a lot of riders ( boy racers) read or are told something, then they go off believeing that they can notice the difference.Having said that, I do realise that experienced riders do notice small changes in settings, tyres etc. I have been riding a long time and honestly I don't believe I would notice the handling difference between a 170 and a 160. I was not aiming my comments at anyone, I was making a statement. Maybe I am way off.

[youngy]

Pretty sure a 170 is a proper fitment on the TRX, as otherwise Dunlop and Michelin wouldn't list it. It is a 5" rim and a 170 is designed for that iirc.

My only experience of wider than stock tyres was a 170 fitted on a ThunderCat, as listed by Dunlop. It really did feel horrible, but that could just as easily have been down to it being a different tyre as much as it being due to the size.

[Killerwhale]

Just a tyre link i found, some comments and stuff....

http://www.roadracers.co.uk/tyres.htm

[youngy]

Had 207s on many bikes without a problem

[steve speed]

i had 207s on my r1 and they were shite ,when we fitted the new bt012ss it was a different bike ,,i am sure tyres make a difference, but just sometimes its in your head ..

[youngy]

It's all in the mind.

[bernardo]

Must have been in my mind as well. I put 207s on my GSXR, worst tyre I've ever used.

[dfh]

My 2 cents worth..

120/70/17 front substitution works well... better ride quality, better feel when on its ear, less knife edge on turn in. Cons? Slows down steering, especially in esses. Cure? slide forks up through the clamps 15mm to restore front ride height... Unexpected bonus bonus? Speedo is now accurate. IMHO gearing for speedo generic bits designed for 70 series front anyway.

170/60/17 rear. Cons? New 170 feels like old, flatspotted 160. Remember that great feeling of your bike feeling new and sharp again every time you fit new tyres? You can avoid that and keep that familiar old baggy feel by fitting a new 170.. Unexpected bonus? Learnt how to sell something on ebay. FS Near new tyre. Only 600km travelled Cost $285... sold for $95.

DFH

[Trixz]

Hmmz

I've got an 120/70 BT014 in stock for a while now, still wondering should or would I do it...

After this thread (and other comment also on the Dutch topic) I'm certain 4 now, soon it will be on my REX

Greetz
Gerben

Ps. and then I have some profile on the sides again

After riding about 400k with a ride out, some months ago, I'm very pleased with the 70!
Only downside is/was that the tyre was not new, so the new BT016 will ride even better

Greetz
Gerben

[idl1975]

so what do you guys think of maybe a 120/70 front and a 170/rear on the std rear rim

I am running a 170/60 at the back and it actually improved the handling. The 160 tended to "thruppeny bit", while the 170 rolls at a more predictable rate. Have not noticed any loss of grip at higher lean angles, including in track use, so at least with my current tyres it doesn't seem to notably reduced the size of the contact patch. I don't see any reason not to try 120/70 and 170/60. I actually went for the 170 just because there was one on e-bay cheap, but it's worked out fine.

dfhs experience makes me think you maybe have to choose your tyre carefully. My 170 feels like it turns in just as fast as you ask it to, but at a consistent rate - i.e. not plunging in and then stabilising. That's a Conti Road Attack with a Sportec M1 front.

[phuk72]

A lot of how a tyre feels has nothing (or very little) to do with size and is more to do with brands and type

The shape of a tyre affects it far more. If you look at the profile of, say something like a BT020, which is very rounded and compare it to something like a Sper Corsa Pro which is very 'pointy' you can reasonably expect different handling characteristics.

Also, actual measured sizes differ across brands.

And you need to bear in mind that most 'comparisons' with a 160 against a 170 are from shagged tyre to new so even a wrong size tyre will feel way better

When I first got my bike it had a virtually new 170 section on it and it was crap. Went to a 160 of the same brand (Pirelli somat or other) and it was way better

Bottom line is that 170 is not recommended fitment and is too big a tyre for the rim. And 160 section is plenty for grip etc

[ekoja]

And in my experience just to add another tangent to all of this, tyre pressures will also alter the handling of your bike. I run 32 front 35 rear which seems to result in a bike that I feel handles really well, and I feel comfortable with. I weight about 90 kgs, and the front forks are I think (without popping out and measuring them) 25mm through the yokes. I have watched a front tyre change it's basic shape just with the addition of a few (insert your preffered pressure reading) ps of air.