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Technically Speaking => Wheels & Tyres => Topic started by: lil4399 on Wednesday, 17 November 2021, 02:45 AM

Title: Tyre deformation
Post by: lil4399 on Wednesday, 17 November 2021, 02:45 AM
In June this year I noticed my front tyre had deformed to a pronounced V shape. Rear was getting thin so changed both for Battleaxe (mate has them on his XJR and really liked them) all seemed fine until today, put it in the dealers to have the throttle bodies synchronized, job went well but he showed me that my front tyre was deforming...

Anyone else had this problem?

Just for info running at 35psi and check them weekly.
Title: Re: Tyre deformation
Post by: Hooli on Wednesday, 17 November 2021, 03:29 AM
Seems quite common, I've had it on several different bikes. Never really found out why, but fresh fork oil, checking the steering bearings and fork bushes has sometimes improved things.
Title: Re: Tyre deformation
Post by: DP1400 on Wednesday, 17 November 2021, 05:42 AM
I had this exact same problem 18 months ago. After a 250mile motorway dash, two-up with a heavily loaded rack. I couldn`t believe it! I put it down to having a harder centre compound than the rest of the tyre (BT021) and inadvertently possibly running it slightly low on air. The bike handled like a pig until I renewed it (BT023).
I will be keeping a close eye on it at the miles tick by......all good to date!
Title: Re: Tyre deformation
Post by: steve porter on Wednesday, 17 November 2021, 05:47 AM
Underinflation
Title: Re: Tyre deformation
Post by: lil4399 on Wednesday, 17 November 2021, 07:13 AM
Quote from: steve porter on Wednesday, 17 November  2021, 05:47 AM
Underinflation


Check the pressures weekly.
Title: Re: Tyre deformation
Post by: KiwiCol on Wednesday, 17 November 2021, 07:17 AM
I'd of thought 35psi was a bit low, handbook recommends 36psi for front & personally I run 38 front & 40 - 42 rear depending on load.   Mind you, I'm a big heavy bloke too.    (.154322 of a short ton)
Title: Re: Tyre deformation
Post by: steve porter on Wednesday, 17 November 2021, 07:35 AM
Gauge could be wrong, if not it's still underinflated so bump it up a few pounds as that's how they wear if they are
Title: Re: Tyre deformation
Post by: lil4399 on Thursday, 18 November 2021, 02:27 AM
I will try 38 psi for a few weeks and monitor it.

I will also strip the forks this winter and refill with new oil as they see a little weak.
Title: Re: Tyre deformation
Post by: Hooli on Thursday, 18 November 2021, 02:35 AM
Check the fork bushes for wear while you're in there.

Parts 8 & 22 in this pic. This is an early fork but the bushes will be in the same place, they stop the lower fork leg wobbling on the end of the sanction. If you lift the bike up & pull on the bottom of the forks, any movement means these bushes are worn out.

Title: Re: Tyre deformation
Post by: grog on Thursday, 18 November 2021, 07:32 PM
I wont ever use Bridgestone, seen 3 or 4 with front tyre just wearing off one side. Mates CB1300, less than 4 th ks, another on low k cb600, stuffed at 5th. Nothing to do with worn forks, low k bikes. Just inferior tyres. Back in 80s had same with A49 Michelin and Dunlop Elites, new tyres, un rideable, thrown in bin. Never had a prob with Pirelli but as said before, Pirelli car tyre lasted one day, flew to pieces. Might seem strange but my experience, had cheap chinese tyres on car, switched to Goodyear, chinese were far better in wet, never a vibration. Have balanced Goodyear 3 or more times, always a bit of shake. Chinese also lasted better, nearly due another set, what to buy?
Title: Re: Tyre deformation
Post by: Jeykey on Friday, 19 November 2021, 08:57 PM
I´ve had this happen to me with a Battlax, can´t remember the model, BT20 I think. In my case, I guess the v-shape had to do with me riding mainly in urban areas where most of the time I can´t lean enough. The lean angles only caught half of the tyre. I´m curious to see how the Michelin Road 5 will do.
Title: Re: Tyre deformation
Post by: Eric GSX1400K3 on Friday, 19 November 2021, 10:02 PM
 Now a few 1000 is I to my BT031's, no issues to date.  Agree living in suburbia just hammers the right hand front, my Daytona675 had tyres worn asymmetrically that bad that the bike just flopped into corners. Its the roundabouts that do it.  New set of tyres sorted it.  The BT031 dual compound don't seem to be too affected by this yet.
Title: Re: Tyre deformation
Post by: Roo on Thursday, 17 February 2022, 01:20 PM
Running Road 4's ,  have been playing around with susp and tyres pressures,just to see ?

Popped in 38 and 40 (cold) and quite like the feel, sharpened her up and feels lighter and less effort..  Don't know about outright grip ,but hey I'm not on a race track anymore.....
I say try stuff, you may like it ?
Title: Re: Tyre deformation
Post by: grog on Thursday, 17 February 2022, 07:20 PM
36/38 for me Roo. Seems to work ok. Pirelli not Michys. Doesnt seem to worry rear but if front goes neglected, sure can notice.Im very fussy on pressure so doesnt happen often
Title: Re: Tyre deformation
Post by: KiwiCol on Friday, 18 February 2022, 01:51 AM
I run 38/40-42 but I'm heavy, bike thinks there's always a pillion on it.
Title: Re: Tyre deformation
Post by: AndyB on Friday, 18 February 2022, 07:12 AM
I'm on pirrellis and run 38 / 40 solo , let the suspension take the bumps not the tyre
Never had a problem with the angel GT's.....mind you, I've not used anything thing else , so I cant compare
Title: Re: Tyre deformation
Post by: Johno on Friday, 18 February 2022, 07:43 AM
Quote from: AndyB on Friday, 18 February  2022, 07:12 AM
I'm on pirrellis and run 38 / 40 solo , let the suspension take the bumps not the tyre
Never had a problem with the angel GT's.....mind you, I've not used anything thing else , so I cant compare

Like Andy I've only used Angel GTs and have been very happy with the grip and wear. Last set were replaced when the front was worn unevenly but I had had the best of the usable rubber.

I've been told by an engineer that road camber is the cause. Says it's a common phenomenon.
Title: Re: Tyre deformation
Post by: VladTepes on Friday, 18 February 2022, 12:29 PM
Was running 36-38, 38-40, now trying 36-40.  TBH I can't see much difference I think the 1400 is pretty forgiving in that relatively narrow band.
Typically most people seem to run 36-38 F and 38-42 rear.
Title: Re: Tyre deformation
Post by: lil4399 on Sunday, 29 January 2023, 02:29 AM
Just looking at an old post, and realised I never responded with what I think was the cause.

Front compression, left leg, 3 screws out, right leg 11 stews out.

Current tyre 7k in and wear even. I did put new oil, bushings and progressive springs in at the same time.