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I have recently had my tyres on my bike changed from mountain bike tyres to road tyres. I was also advised by the man who fixed it that my saddle was too low for me and he raised it. Since these changes it almost feels like I am cycling with slightly flat tyres. Uphill doesn't feel massively strenuous but I just wanted to see if this is normal or not?

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    Could you tell us the model and sizes of the old and new tyres? Depending on how knobbly your old MTB tyres were, you may just be used to the kind of 'buzz' they produce as you ride along, whilst smooth road tyres will be lacking this. Different tyres do produce diferent road feel and feedback though. – ilikeprogramming Aug 23 '16 at 8:45
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    Call it silly - but are you running the new tyres at the same pressure as your old MTB tyres? Could be the new tyres require a higher pressure (this will be written on the sidewall) so yes, you could be riding low. – Criggie Aug 23 '16 at 11:09
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    Check your tire pressure. And for road riding run the tires at a pressure near the top limit on the tire sidewall. (As ilike suggests, you're likely not feeling the bump-bump-bump of your old knobbies.) – Daniel R Hicks Aug 23 '16 at 11:57
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Re: your saddle being too low.

One way to check if it's at the correct height is to sit on your seat, put one foot on the pedal and try to "straighten" your leg - with the pedal at it's lowest point (the other being at the top) there should be a slight bend to your leg.

This video's quite informative: seat height

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    If it feels low it is too low. And if your hips wiggle while you ride, its too high. Finding the happy medium is often trial and error for a while. – Criggie Aug 23 '16 at 11:10
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Raising the seat height will allow for a more efficient pedal stroke. Too low a seat height tends to "burn" the thigh muscles. And cause a loss of power - especially on the down-stroke as you come through the pedals.

The main difference by changing from mountain bike to road tires will be the tire pressure. Road tires - even on MTB - are pumped up to a higher psi than off-road tyre. Consequently the contact patch is smaller with the road and the rolling resistance reduced. A side-effect of this would be the sound and feel of your tires on tarmac will be different to your old tires.

  • Further, having a seat far too low places undue stress on the knees. – Daniel R Hicks Oct 12 '16 at 11:41
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There is no correlation between tyres and seat height that I know of. Road tyres are not as high, so with them on the bike itself would be a bit lower overall. But that's got nothing to do with the seat.

So my 29'er mountain bike and my 700 touring bike both have the same seat height in relation to the pedals, but the touring bike sits lower to the ground and took a tiny bit of getting used to. Both in looking at the pathetically little bit of rubber between me and the road and handling-wise. I still feel happier with the bigger fatter tyres, especially when throwing the bike around.

So I wouldn't think this is normal, unless the guy had another reason for raising the seat.

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    It's plausible that (in the mechanic's had at least) you might want the seat a touch on the low side for MTB riding to get your feet down more easily. But the optimal seat height is, as you say, based on the pedal - saddle distance. – Chris H Aug 23 '16 at 14:26
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    I'm sure the seat and tyres were completely independent of each other. If a mechanic said to you, "You need a new chain and new brake blocks," you wouldn't start explaining how changing the chain makes no difference to the brakes. You'd just assume that your chain and your brake blocks were both worn out. – David Richerby Oct 12 '16 at 7:52
  • @DavidRicherby the last sentence basically says that. – Kilisi Oct 12 '16 at 9:40
  • @Kilisi But the whole answer is a straw man. You're starting with the unlikely assumption that the mechanic believes that changing the tyres requires adjusting the seat height, devoting almost your whole answer to this and then disclaiming with, "Oh, but if he had a non-ridiculous reason for changing the seat height, then it might be OK." – David Richerby Oct 12 '16 at 9:54
  • @DavidRicherby I'm a comp tech, I've seen people change RAM and charge for it that had nothing wrong with it. I've seen car mechanics loosen fan belts so it makes that horrible screeching noise and then try and charge my mother for all sorts of things... It's NOT normal to adjust something for a client and not explain why. – Kilisi Oct 12 '16 at 9:58

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