Saw tooth tyre wear pattern

[machten]

I'm getting this saw tooth tyre wear on the front tyre of my 1968 Mark 3 D. The tyre is a Michelin M45 that was on the bike when I got it back in 2010, and I keep it inflated to the correct pressure. The back tyre is also an M45 and doesn't display this wear pattern. In the picture below the direction of normal rotation is anti-clockwise.



The front forks seem to behave very well under normal use and braking, but I assume that has to be where the cause lies.

Has anyone any guidance or similar experience thay can share?

kev

[Bevel bob]

Out of balance?.

[LaceyDucati]

Kev

All front tyres tend to wear like this to some extent due to braking forces. It is probably more pronounced on this tyre as it has large blocks and is maybe soft rubber and is more intended for light weight commuter bikes. The pressure may be to low, how did you determine the correct pressure? It is quite likely the handbook original pressure is wrong for an after market tyre. If Michelin do not quote a pressure (which is quite likely) then you need to make an educated guess at pressure and experiment. What pressures were you using?

Nigel

[Ventodue]

Have had something similar on big bikes wearing Bridgestone BT45s, Kev. My Laverda Corsa is the worse affected. It sets up a nasty sideways rocking motion, especially on long sweepers. Most unpleasant. (I run with Bridgestone's recommended pressure which is higher than the recommended pressure at the time).

Don't know how to prevent it, but dropping the pressure a little reduces the rocking motion. The next step is new tyres (the rear's normally run its course by now anyways ).

Craig

P.s Doesn't happen with Avons, btw. But they don't last as long. So strongly suspect it's down to compound - like wot Nigel implies.

[machten]

Guys,

Thanks for the responses.

Bob, as the wear pattern is consistent all around the tyre and I have no vibration other than what I reasonably assume is from the tyre wear itself (more a road whine than a vibration), I'm pretty sure it's not a balance issue.

Nigel raises a very good question. To paraphrase ...."On what do you base your assumption that you're running it at the right pressure?" The answer is "no great documentation at all". I run it between 32 and 34 psi and only because that has served me well "traditionally" with my twins, and it kind of "feels right".

Craig...I use BT45's on my 900's and love them and I certainly don't get this effect. On my Sport I use Avons ( because I'm a solid devotee of the sporting aspect of their tyres and I firmly believe the Avon 19 90/90 on the front has a beneficial quickening effect on 750 Sport steering and I don't mind sacrificing longivity for performance on that bike). I'm experimenting at the moment with Metzler Lasertecs on my 750 GT at the moment, and they seem "OK", but early days as far as durability is concerned.

In all cases, I run pressures between 32 and 34 on the front and 34 and 36 on the back.

Perhaps this block pattern is not a good solution for the 250 M3D?

All advice appreciated, fellas!!!

Kev

[machten]

One other piece of information....

Nigel said....

It is probably more pronounced on this tyre as it has large blocks and is maybe soft rubber and is more intended for light weight commuter bikes.

I think Nigel is correct that it is "soft rubber". I've had two occasions on this bike where I've had to avoid some goose on the road and get the bike sideways with both brakes on. The tyres release into a sideways skid slowly and grip back slowly in a very controllable manner. I'm no expert speedway rider or anything, so I suspect it is pretty soft (and forgiving) rubber.

Kev

[LaceyDucati]

Kev

Okay, pressure seems more on the high side for a single, so not under inflated, but if it works for you....

I generally run around 30ish in the front and 32ish in the back using BT45's on my 350 mark3. But I guess it's not so warm here in the UK. On my 900 GTS I ran BT45's at the Bridgestone recommendation with no problems. Only problem I had was, I shot through a set in 3000 miles, mind you that was across France, Spain and Portugal in high temperatures two up with luggage. I've since like you put on Metzler Lasertecs on but still not done enough mileage to be sure . I haven't noticed anything bad in a 1000 miles and reports are of much greater mileages. Looks promising.

I'm up for trying the German Heidenau tyres on singles with smaller size requirements. All I need is time to complete a restoration on a bike to try them on! Be very interested to here from anyone using them already. May even consider stocking them for the business.

Best Wishes Nigel

[graeme]

Hello Kev,

Dunlop TT100 GP work well on a single, they last about 3000 kms before the rear needs replacing. Hang on well and don't sawtooth. Good in the wet too.
28-30 front and 34 rear work for me.

Graeme

[Ventodue]

Bit off topic 'cos it ain't singles; but, begging the indulgence of the Moderators ...

Craig...I use BT45's on my 900's and love them and I certainly don't get this effect. <snip> In all cases, I run pressures between 32 and 34 on the front and 34 and 36 on the back.

Yeh, that could be the prob with my Corsa. Bridgestone's recommended presuures are 36 front and 41 rear, both of which seem kinda high ... This is the effect, btw - hard to photo, but all the leading edges (as arrowed) are raised. I've had recommendations that Pirelli Sport Demons are an ok alternative, btw.



Back on topic, i.e singles

I like Graeme's suggestion of Dunlop TT100s. I have these on my Scrambler while on the Vento, I have Dunlops K82 which use the same tread pattern. They seem to both grip and last ok.

Ciao

Craig

[remery]

I thought trail braking tended to have that effect on tires.