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Tyre Rub – Do I need to change for smaller tyres?

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  • April 13, 2017 at 7:36 am #27003
    MonkeyPuzzle

    Based on wrong tyre clearances for my frame given in a Cyclist.co.uk review, I bought some Schwalbe G-Ones in 35mm flavour. The rear fits fine and dandy, but the front has ~1mm clearance at the top of the fork and when I get out of the saddle or put the power down (if you can call it that!) I can hear a rhythmic tyre buzz from my front fork matched to my pedal strokes. I don’t notice any resistance and when spinning normally, seated, there’s nothing audible at all.

     

    Am I going to stuff the fork if I carry on like this? I love the tyres after setting up tubeless, and it’d be a shame to take the hit for selling nearly new tyres that were expensive to buy. Obviously, selling and replacing those would be cheaper than doing the same for the fork!

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  • April 19, 2017 at 2:26 pm #891171
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    beezus fufoon
    guyrwood wrote:
    Do you mean HGV tyres? They run at 90-130 ish depending whether they’re on the truck or the trailer. If you’ve ever been sitting in your car when an HGV has a blow-out nearby, you’ll need clean underwear  .

    ah, you’re right – that would explain it – no idea where I got that from!

    April 19, 2017 at 2:04 pm #891169
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    StraelGuy

    Do you mean HGV tyres? They

    Do you mean HGV tyres? They run at 90-130 ish depending whether they’re on the truck or the trailer. If you’ve ever been sitting in your car when an HGV has a blow-out nearby, you’ll need clean underwear  .

    April 19, 2017 at 1:20 pm #891167
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    beezus fufoon
    TypeVertigo wrote:
    beezus fufoon wrote:
    TypeVertigo wrote:
    I learned the hard way that running 70 psi in a 28 mm tire will cause a 32 mm tire to grip less effectively.

    is it like string theory where the pressure in the 28mm affects the grip of the 32mm?

    Hahaha that came out wrong. 🙂

    I meant 70 psi on 32 mm tire doesn’t return the same resulting grip as 70 psi on a 28 mm tire. If anything it’s actually worse on the wider tire…so better to run the wider tire with even less pressure to get the same grip.

    yes, that makes sense

    those huge truck tyres run at something like 10-15psi, but if they blow they still put out enough force to send you flying – something to do with pressure relative to volume

    April 19, 2017 at 1:14 pm #891165
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    TypeVertigo
    beezus fufoon wrote:
    TypeVertigo wrote:
    I learned the hard way that running 70 psi in a 28 mm tire will cause a 32 mm tire to grip less effectively.

    is it like string theory where the pressure in the 28mm affects the grip of the 32mm?

    Hahaha that came out wrong. 🙂

    I meant 70 psi on 32 mm tire doesn’t return the same resulting grip as 70 psi on a 28 mm tire. If anything it’s actually worse on the wider tire…so better to run the wider tire with even less pressure to get the same grip.

    April 17, 2017 at 2:44 pm #891163
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    beezus fufoon

    TypeVertigo wrote:

    TypeVertigo wrote:
    I learned the hard way that running 70 psi in a 28 mm tire will cause a 32 mm tire to grip less effectively.

    is it like string theory where the pressure in the 28mm affects the grip of the 32mm?

    April 17, 2017 at 2:10 pm #891161
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    TypeVertigo

    CXR94Di2 wrote:

    CXR94Di2 wrote:
    You need to be going some to break traction on a Schwalbe 28mm tyre. You could alter the grip by lowering the pressure a bit.

    I learned the hard way that running 70 psi in a 28 mm tire will cause a 32 mm tire to grip less effectively. Overinflation tends to do that, in my experience. Make a tire too hard and it will actually lose its ability to deform to the road surface and get grip.

    To my astonishment, the 32 mm tires I’m running are actually happiest at 40-50 psi. They’re not even tubeless.

    April 14, 2017 at 8:10 am #891159
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    Anonymous

    So, you need to find another

    So, you need to find another tubeless tyre manufacturer that makes a 35mm tyre true to size (if not a little under). Panaracer, Clement, Hutchinson, Bontrager, Specialized all come to mind. Keep the G-One as a replacement for when the rear wears.

    April 13, 2017 at 5:39 pm #891157
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    CXR94Di2

    You need to be going some to
    You need to be going some to break traction on a Schwalbe 28mm tyre. You could alter the grip by lowering the pressure a bit.

    April 13, 2017 at 5:33 pm #891155
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    MonkeyPuzzle

    At the cost of Schwalbe tyres

    At the cost of Schwalbe tyres, there should be some resale in them! Seriously though, with less than 40km on them, they are basically new. 

    Is having a wider tyre on the back a great idea? If I’m going to lose traction I’d prefer the back to slide before the front.

    April 13, 2017 at 3:55 pm #891153
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    Kapelmuur

    I didn’t realise that there

    I didn’t realise that there was any resale value in used bike tyres.

    Why not replace the front tyre as suggested and keep it for when the rear one wears out? 

     

    April 13, 2017 at 3:16 pm #891151
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    MonkeyPuzzle

    Sorry I’ve explained that

    Sorry I’ve explained that poorly. The ~1mm is to either side of the tyre at the widest point. It’s disc brakes so callipers not an issue.

    April 13, 2017 at 2:02 pm #891149
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    sparker

    Try to see if it is the fork

    Try to see if it is the fork or the caliper causing the rub. I put some 28s on my Trek for Roubaix last year which rubbed the same way you’re describing. However, changing my 6800 Ultegra calipers for 6700 Ultegras gave me just enough extra room. The 6800 was narrower due to a more ‘bulbous’ design, for want of a better word.

    April 13, 2017 at 12:30 pm #891147
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    surly_by_name

    Lower pressure will help but

    Lower pressure will help but this is a temporary solution and you need a new (smaller) tyre. Remove current one while its still saleable on ebay as “hardly used”.

    April 13, 2017 at 12:02 pm #891145
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    peted76

    I had a similar issue on my

    I had a similar issue on my old TCR, put 25mm schwables on to wide rims and it left very little clearance.. the front was okay, but the rear clearance with the brake caliper was a problem, In the wet I’d pick up debris, which caused rub and scratches, once I had to dig the mud out with a stick it was that clogged. Then at the top of Alp d’huez, the day prior to the marmotte, my rear tyre ‘ripped’ I’d gone over a very slightly sticky bit of tarmac, picked up a stone which jammed under my caliper and ripped a hole in the tyre casing. 

    April 13, 2017 at 10:16 am #891143
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    Anonymous

    That 1mm vertical clearance

    That 1mm vertical clearance is a tad small in my opinion – pick up some mud or similar and it will drag through and (repetatively) over time wear away some of the crown. The buzzing is no doubt the side to side movement of the wheel – you must have a very small lateral gap too. Similarly, this is not good for the fork in the long run. You have two choices – always remain seated when cycling or fit a narrower tyre. You can possibly still put a 35mm tyre from another manufacturer which actually measures 35mm. Schwalbe are notorious for coming out wider than stated (my 25mm Pro-One’s come out at 27.3mm on Ultegra rims). Running a lower tyre pressure will also help a little.

     

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