Which road in Greenwich?
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Which road in Greenwich?
Racing roadkill
Guru
Get a trike, fit it with Tannus tyres, job's a goodun.
Racing roadkill
Guru
These are what you need.
Ajax Bay
Guru
- Location
- East Devon
No, I'm trying to determine if you have your tyres over inflated, and IMO you have. This will increase your rolling resistance as well (I know, it's counter-intuitive but true) and means you have less tyre in contact with the road (note I am not saying that this means less grip). You may bounce a bit more (no contact) than needed, as well as the comfort bit.
For a load of 84kg split 45-55% front/rear gives ~ 38kg/46kg. If your 25s ARE 25mm wide, tyre pressures should be: 75psi on the front and 90psi on the rear. This is based on having them at the lowest pressure consistent with avoiding pinch flats. See the attached 'Tyre Pressures' article which has biblical prestige.
Your bike + rider weight total is the same as mine and I run 28s which actually measure 26mm at the pressures I use: 72 and 85 (obviously my pump cannot get them that accurate and is not calibrated, but it gives me a target to aim for).
OP
OP
AndyCh
Über Member
'Tis true that with my pressures up like that it makes for a less comfortable ride (with some crashing and bouncing), but I always though the trade off was pace.
Apologies for being dense, but I'm not following the 28s = 26 bit and implying that 25s don't = 25s. Can you explain please?
Apologies for being dense, but I'm not following the 28s = 26 bit and implying that 25s don't = 25s. Can you explain please?
Ajax Bay
Guru
- Location
- East Devon
I refer the honourable member to my post a while ago, during a brief OCD phase, for an insight into my 28-622 tyre widths at different pressures:
https://www.cyclechat.net/threads/n...-my-rights-to-return-them.202764/post-4334295
Each mm less = 5psi more in the tyres for the same load
OP
OP
AndyCh
Über Member
Indeed. I popped up pretty quickly just in case, fearing the whack from behind, as it were.
Phew. Are you doing physics O level? Certainly seems enough to be heading towards a pass mark, just for coming up with such an experiment.
I have to admit that I didn't measure the actual widths of my tyres after the incident, nor before. In fact, I never have. I did think they were just 25s, but I now see that I was wrong.
steveindenmark
Legendary Member
I have gone full circle. Schwalbe Marathon Plus, Continental 4 Season, Schwalbe Dorano and back to Marathon Plus.
I have never had a punctures with Marathon Plus but in the last 2 weeks I have had 3 punctures with the Continentals and the Doranos. Those little bits of stone have become super sharp now they are constantly wet.
I have never had a punctures with Marathon Plus but in the last 2 weeks I have had 3 punctures with the Continentals and the Doranos. Those little bits of stone have become super sharp now they are constantly wet.
