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Correct tyre pressures for my trek FX 7.3 [700x32]?

by APOLLO118
Mon, Apr 01, 2019 15:56
10

Hi chaps, I am confused about what tyre pressures I need for front and rear, can anyone give me advice please and show me how to work pressures out and I would be very grateful, Thank you,  I have the following information:

I weigh 15 stone 3 Ibs [97 Kg].

Bike weighs 3 stone [19 Kg].

Tyres are Continental 4 seasons 700 x 32.

I ride on Tarmac/cycle lanes.

If you're new please join in and if you have questions pop them below and the forum regulars will answer as best we can.

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10 comments

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APOLLO118 | 5 years ago
1 like

A very big thank you to everyone for the help and comments, I will get out and see what works best, thanks again. laugh

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madcarew | 5 years ago
1 like

Really, it's not important. You'll know if they're too soft because when you go over bumps you'll feel the rims hit. Somewhere between 60 and 90 will work just fine. You can probably run 40 if you want a really squishy ride.

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Dr Winston | 5 years ago
1 like

70-80 and don’t over think it....

Personally i’d Be happy with 50 given our crappy roads but I’d end up with too many punch punctures on the even ceappier pot hole bits.

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Nat Jas Moe | 5 years ago
1 like

Using mavic's calculator for a tube set up 73 psi / 5 bar all round ( it's a free app) but you can set up different parameters such as rim width which may affect the final choice.

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Simon E | 5 years ago
1 like

For 32mm tyres and the weights you have given I'd begin with 90 PSI in the rear and 75~80 in the front. Adjust each in 10 psi steps until you are happy with how it feels.

If your gauge uses bar instead of PSI then try 6~6.5 rear, 5~5.5 front.

Please take any tyre advice with a pinch of salt, whether from the manufacturer (they have potential lawsuits to consider), a forumite or any kind of 'guru' or so-called expert.

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BehindTheBikesheds replied to Simon E | 5 years ago
1 like

Simon E wrote:

For 32mm tyres and the weights you have given I'd begin with 90 PSI in the rear and 75~80 in the front. Adjust each in 10 psi steps until you are happy with how it feels.

If your gauge uses bar instead of PSI then try 6~6.5 rear, 5~5.5 front.

Please take any tyre advice with a pinch of salt, whether from the manufacturer (they have potential lawsuits to consider), a forumite or any kind of 'guru' or so-called expert.

For 32s that's way, way too high, I like my tyres pretty well inflated but suggesting starting with 90 for the rear is too much even with a 60/40 weight distribution, 75-80psi for the front is also well off! Have you actualy tried riding these pressures on that size tyre with that equivalent load, I have and it's bumpy as fuck on all but the very smoothest bits of tarmac, that's with compliant carbon flat bar, carbon fork and carbon seat stays and seatpost. Your equivalence to the pressures you are suggesting for 32s is like putting 136/110psi for 25mm tyres, bonkers!

Sure if you have a super smooth road for every single mile you have you could get away with that, but not for most roads you're going to experience in the UK, also you're wrong with suggesting adjusting 10PSI at a time, this is too big a step, you're likely to miss the sweetspot doing it that way, 5psi at a time at the very most.

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BehindTheBikesheds | 5 years ago
1 like

There's a berto based calculator online somewhere.

I'm about your weight and ride a specialized globe pro as my daily( *) currently running 32r/28f, I usually stick about 80psi in each unloaded, if 32/32 then I'd go with 80psi rear and about 55 front and see how that feels, for some it might be too much and they want a softer ride, others maybe more.

If you're carrying circa 10kg loads in panniers regularly then I'd stick in another 5-7 at the back and maybe 2 track pump squirts at the front.

Your weight distribution on the FX will vary compared to a drop bar bike, more like 60/40 as opposed to 55/45.

* I'd recheck your FX weight as I doubt very much even with guards, a rack+ lights etc it'd be anywhere near 19kg, at least 5kg lighter even with pannier bags on board.

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jollygoodvelo | 5 years ago
2 likes

70psi.  Now go ride your bike.

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janusz0 | 5 years ago
1 like

Ask your favourite search engine to look up "Frank Berto Tire Pressures" (he's a good guy from the USA), or trust this website: https://road.cc/content/feature/180830-how-choose-your-tyre-pressure-bal...

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Mr Pennington | 5 years ago
1 like

The graphs on this  page may help - https://www.google.com/search?client=firefox-b-1-d&tbm=isch&q=continenta...

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