Tyre sizes

Discussion in 'Road Cycling' started by Quick Shifter, Dec 5, 2018.

  1. Quick Shifter

    Quick Shifter New Member

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    I am a recreational road cyclist. I have three bikes, all fitted with 700 x 23 tyres - two older bikes with the narrow rims of the time and my latest with H Plus Son wider rims. All the tyres are in perfect condition; is it worth the expense of swapping them for 700 x 25 tyres? Will I notice any difference?
     
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  2. dabac

    dabac Well-Known Member

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    ”Worth it” for a recreational rider, and ”will I notice” are hopelessly undefined phrases. Some people will claim to notice nearly any change, no matter how far-fetched.
    Have you ever found yourself thinking:”man, this ride is harsh”?
    If you have, and at a sensible tire pressure for your riding conditions, then you might benefit from a change.
    I almost never replace tires in good condition, unless there’s a very compelling argument that I have something important to gain from it.
    But with the amount of riding I do, tires do wear out. So life naturally offers me chances to replace them with something else.
    What you could do is get one wider tire, mount it to a rear and do some rides at a couple of different tire pressures. That will give you SOME baseline for a comparison.
    Assuming you - until now - have considered your current tires as fit-for-purpose, I suggest you stick with make & model, and only change size. Otherwise you’ll be comparing both different sizes AND models at the same time. That’ll make it extra tricky to judge which change is doing what.
    The H+son rim may ”need” a 28 mm tire for a supposedly optimal configuration.
     
  3. cyclintom

    cyclintom Well-Known Member

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    A great deal of that depends on your size and weight. For limited yearly mileage it probably does matter. But if you are over 150 lbs and an improving rider it would probably make a difference but you might not be able to know it without a lot of experience. Your cornering and the way you hit bumps etc. is still changing and it would be difficult to tell the difference in your riding changes and the tires.
     
  4. Mr. Beanz

    Mr. Beanz Well-Known Member

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    Big rider, 230-260 depending on condition, max mileage year 7300 miles. 24 years on 700 X 23's, never a problem with tires.

    Tried 25's but didn't notice a difference. Why swap the tires on all 7 bikes for no reason? :D

    If I do happen to try a different tire, I wear out the good set first as mentioned earlier.
     
  5. Quick Shifter

    Quick Shifter New Member

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    Difficult to know if I would notice much benefit without trying the 25's, but it seems a waste to discard perfectly good tyres.... I would appreciate a softer ride though; I'm about 165 lbs, so they may be some benefit. Tyres seem to have become horrendously expensive here in the UK recently, has anyone else noticed this and if so, is there a reason for it?
     
  6. cyclintom

    cyclintom Well-Known Member

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    If you change to 25's you have to drop tire pressure around 15-20 psi. The idea is that a larger tire with more air capacity can support the same weight at a lower pressure. It was absolutely impossible to ride my Time VX with 23 mm tires on it without your butt being slammed though your vocal cords. Changing to 28's and 85 psi made it one of the best bikes I've ridden.
     
  7. cyclintom

    cyclintom Well-Known Member

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    At 165 lbs you'd have to be pretty experienced to notice a difference between 23's and 25's with the proper pressure in both.
     
  8. Mr. Beanz

    Mr. Beanz Well-Known Member

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    I believe that works for some people but as we all know, everybody is different. I tried the lower pressure as well with the wider tires and no thanks, NOT FOR ME!

    Every crack in the road felt like a pinch flat and the descents were really scary. I could feel the tires sinking and giving with lower pressure. I had to slow way down in order to feel safe. On these mtn road switchbacks, I feel safe with hard tires that feel like riding on rails vs the soft giving feel.

    Same with low spoke count wheels. Being a bigger rider, I feel the rims flex in the tight switchbacks at speeds of 30+. I prefer a hard tire and a stiff rim like Deep V's (30 MM deep).

    Feeling safe is my priority and with soft tires and rims, no thank you!

    I've ridden an MTB down these switchbacks as well and no thanks! Those big soft tires are meant for the dirt. I just don't feel safe on soft tires and wheels.

    Switchbacks for 8 straight miles at 30+? No thanks, I'll keep my tires pumped!

    0000bikegina.JPG
     
  9. BrianNystrom

    BrianNystrom Member

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    If anything, wider tires should feel more secure, so something's not right here. How much did you drop the pressure? At your weight, with 25mm tires, you'll probably need to run 90 psi front and 100 rear, perhaps more. The difference in volume between 23 and 25mm tires is pretty small, so the change in pressure shouldn't be large either, perhaps on the order of 10 psi as a starting point. If you spend some time tweaking the tire pressure to suit yourself, you should find that the wider rubber is both more comfortable and more secure.

    It's also important to compare similar tires. The soft feels of the MTB tires is largely due to tread squirm. If the road tires you compared had substantially different tread thickness or material, that might also explain some of what you felt.

    Another consideration is that more comfortable tire/pressure combinations eliminate a lot of road buzz, which can give the impression that the tires are soft when the actually aren't. Since you've been riding narrow tires at high pressure for a long time, this will be quite noticeable and it will take some time to get used to it. Once you do and you start reaping the rewards of increased comfort and improved traction, you'll be glad to you took the time to make the switch.

    What I did was gradually lower the tire pressure over the course of many rides. until I could really tell that they were too soft, then bump it back up until they were firm enough to feel solid. It gave me time to get used to the new feel and made it possible to tell when I truly reached the lower limit.
     
    #9 BrianNystrom, Dec 6, 2018
    Last edited: Dec 6, 2018
  10. dabac

    dabac Well-Known Member

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    You’re missing a point here: Beanz says he ”feels” safer on firmer tires. There’s no point in arguing about how another person feels. That’s his truth, and we can’t experience it.
    All you can do is suggest that he tries something else with an open mind, and tries to figure out why he feels safer on the firmer tires.
    If Beanz come to the conclsion that he can’t tie his feeling to an actual handling improvement, then maybe he’ll change his opinion.
    I have a riding buddy who got started on narrow, high pressure sew-ups. Despite Strava, HRM and power meters telling him otherwise, he still feels faster on his old-school, bone-jarring ride.
    To him, that’s how race day should feel like, reality be damned.
     
  11. Mr. Beanz

    Mr. Beanz Well-Known Member

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    Thank you! :cool:
     
  12. BrianNystrom

    BrianNystrom Member

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    I fully understood what Mr. Beanz said and I've been there myself. What I was trying to point out is that the bike will feel different after you switch to wider tires and that it takes a little time for your perception of the ride to change. Whether he tries it again or not is entirely up to him and if he decides to stay with his older setup, that's fine if it's what make him happy. I'd just hate to see him miss out on a good thing simply by not giving it a sufficient trial.

    BTW, you can make wider tires as firm as you want; it's simply a matter of adjusting the air pressure. You'll still gain the advantages of decreased rolling resistance and better traction.
     
  13. cyclintom

    cyclintom Well-Known Member

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    Well, you're pretty heavy and you really have to get used to lower pressures in a tire. If it feels like a pinch flat then you certainly aren't high enough pressure. I'm 185 lbs and have run as low as 65 lbs and while hitting some potholes at the pressure did feel odd, but no flats. So I think that you have to learn what pressure you can run for your own weight.
     
  14. cyclintom

    cyclintom Well-Known Member

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    We can agree on that. Riding wider lower pressure tires definitely feels different but once you start being able to feel the difference with wider tires you can then tell the much harsher ride of the narrower high pressure tires. I started at a time when we all used 20 mm tires pumped up to some horrible pressure and if you hit a goats head they would literally explode. And you couldn't pump them up to that pressure on the road with a hand pump. Then changing over to 23's you could pump them up with these Silca frame pumps. Now using 25's or 28's they run at low enough pressures that you only have to pump them up a couple of times a week and that is riding them 150 miles a week.
     
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