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I have a Trek FX3 with Bontrager AW1 Hard-Case Lite, 700x32c and I would like to know what the maximum tire pressure is? The reason I ask is when riding at higher speeds and turning it feels like the back tire is going to come off.

I found this article on bontrager tire pressures but it is unclear which precise model of tire I have as there is no combination of AW1 and Hard-Case Lite?

UPDATE

I inflated the tires to 85psi and the issue has gone away (they were at 55 psi). Went on a 40 mile ride and noticed a significant improvement in the bike performance and stability.

Thank you for the help.

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  • Your pressure might be too high then - best to experiment and find what feels best to you.
    – Criggie ♦
    Aug 1, 2017 at 20:14

3 Answers 3

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The maximum tire pressure should be written on the sidewalls. Often the embossed lettering is hard to read, shining a flashlight at an angle can give you the contrast to make it easier to read.

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The min and max pressures for a tire are written on its sidewalls.

Funny that the Bontrager table does not have an entry for AW1 Hard-Case Lite 700x32c, however, I notice that the pressures for AW1 Hard Case and AW2 Hard Case Lite for each of 20, 23 and 28 mm sizes are the same, so you should be safe with the specified pressure for the AW2 tire: 55-100 psi, 3.8-6.9 bar.

Update:

To get a feeling a tire is coming off a rim in a turn you would have to be running a very low tire pressure, probably less than the minimum specified. 70 - 80 psi in that tire should be fine. If increasing the pressure does not help, there may be another issue with your rear wheel.

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The max pressure should be written on the tire's sidewall. If you haven't felt it sluggish or squirming at low speeds, then your tire should be quite well inflated. If the tire is inflated over its min pressure, and it seems that it is, then there's really little chance that it will come off.

A normal pressure for a 32C tire is around 4.5 to 5.5 bars or 65 to 80 psi for an avg weight person on an unloaded bike, usually, there's no reason to go above that. (If you weigh over 80-90kg, then you can go a bit higher)

Option #1: Your hub is loose (or your spokes are not tensioned well, but this is not likely). Your rear wheel should not have any side to side movement, other than a small flex from the spokes. Some wheels are more flexy than others, but you shouldn't feel any play in the hub. If there's play, then it's the best to take it to your LBS.

Option #2: Probably you corner so fast/hard, that your tire does not have enough grip on that given road surface and you're sliding a bit as you hit the limits of the tire.

Option #3: Your tire is one that squirms that much even at the right pressures. You should not over inflate your tire because of this as it will decrease the grip, comfort and over a point even rolling resistance. You have to find the sweet spot that works the best for you. Also note, that a tire inflated over its max pressure is not safe and I wouldn't run any tire near to its max pressure, if there isn't a good reason, like carrying a heavy load or being really over weight.

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  • Tires with low pressure squirm, which produces the sideslip that feels very similar to actual sliding. By the way, the current Marathon is very grippy but has tall flexy tread that squirms even with high pressure. Once you get used to the slippy feeling and understeering, you can corner quite hard on them.
    – ojs
    Aug 2, 2017 at 18:49
  • Before I had a Marathon Supreme on, the same size, same pressure. I never felt anything similar. Even earlier I had Marathon Pluses (same compound) and on a slippery, wet local road I was lucky to stay up. I don't think that they're very grippy, probably they're above the avg cheap tire. On the other hand, I didn't go down with Marathon ( it was only on the rear). So I won't say that they don't squirm. But with this logic, the OP wants to overinflate their tyres because he doesn't like the squirm they have. But this is a bad practice and should not be done.
    – PPatrik
    Aug 3, 2017 at 10:33
  • So, you don't have any idea what you are talking about?
    – ojs
    Aug 3, 2017 at 17:06
  • Please think about the rules, before posting your comment. You said 2 things: the Marathons squirm and the Marathons are very grippy. First, I wrote that the Marathons are NOT very grippy, then you haven't been on grippy tires. 2.: I thought about the squirming: I didn't fall then, so probably they squirm that much, as you said, but we don't know. 3.: I shared my experience that the same sized Supreme at the same pressure won't squirm, even though it's a more flexible tire. These are 3 contradictory facts and at this point, I don't want to decide which is true.
    – PPatrik
    Aug 3, 2017 at 20:15
  • Finally: The OP should not over inflate his tires. The maximum pressure written on the tire is the absolute maximum which the tire can safely support. Those who are new to cycling will say that the higher pressure is better, but this is not the case. At lower pressures, you get more grip, more comfort and until a point lower rolling resistance ( in real world conditions). So the answer is: The OP should find the sweet spot between acceptable squirm, comfort and rolling resistance. I will edit my answer accordingly. (Please in your next comment stay on the topic!)
    – PPatrik
    Aug 3, 2017 at 20:31

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