What should my next bike be?

For discussions about bikes and equipment.
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Re: What should my next bike be?

Postby 531colin » 12 Aug 2019, 10:36pm

One with a slack seat tube angle.

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Re: What should my next bike be?

Postby NetworkMan » 13 Aug 2019, 11:49am

If you are interested in changing tyres you might care to peruse:-
https://www.bicyclerollingresistance.co ... ke-reviews

You'll see a comparison of road bike tyres, all tests are 25 mm ones. These tests are all done on a roller with a rough surface and there is much debate about how well these results reflect likely performance on a real road. However:-
While the absolute power measurements may not be valid it's likely that the relative rankings probably are. This supported by the observation that of the touring tyres tested (not on the road list) the Vittoria Voyager Hyper appears second on the list and many people on this forum are very pleased with it.

You'll see that there is a trade-off between low rolling resistance and high puncture resistance. The Gatorskin has good puncture resistance but pretty high rolling resistance; I've recently replaced mine with something which rolls better. At the time I thought it was between the Schwalbe One Evo (similar to the Schwalbe One V-Guard in the table but probably a little better) and the Continental Grand Prix 4000S II). I got the Schwalbe mainly because of price. Since then Continental have brought out the new GP 5000 which looks pretty impressive though less puncture resistant than the Schwalbe and the MIchelin Power Competition looks good too.

In the table it's universally true that higher pressures mean lower rolling resistance. On a smooth(ish) surface that's true but on a rough road it almost certainly isn't. This is because a low pressure can reduce vibration transmitted to bike and, especially, to rider. Vibrating a rider results in lost energy which shows up as additional rolling resistance as well as being less comfortable. You therefore need to experiment with tyre pressure.

I'd agree with observation that the frame it unlikely to be responsible for any weight problem. In https://forum.cyclinguk.org/viewtopic.php?f=5&t=129426 there is mention of two bikes using the same basic design of frame, one is in steel, the other is mine in titanium. My titanium frame weighs about 300 gm less but because the steel bike it kitted out as a semi-racer rather than a light tourer it weighs about 1.1 kg. less!

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Re: What should my next bike be?

Postby Brianjeff50 » 13 Aug 2019, 8:43pm

531colin wrote:One with a slack seat tube angle.

Having spent my youth and now my oap years picking up bikes that just happened along I’ve never got to learn much about slack seat tube angles and other nuances of frame design.
Any pointers as to where I could go to start filling in the gaps in my cycling education?

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Re: What should my next bike be?

Postby 531colin » 13 Aug 2019, 9:06pm

Its my recollection that you had a bike fit with your current bike, and to get the saddle far enough back required both a long layback seatpost and a saddle with long rails. So, if it was me, I would look up the geo. of the current bike to find what the seat tube angle is; I would then be looking ideally for a bike with a slacker seat tube angle than the existing bike, because this would give you a bit of wriggle room, instead of having to get the saddle as far back as possible, you might (for example) be able to choose a saddle on the basis of comfort, rather than the length of the rails. For somebody of "average male height" one degree slacker seat tube angle (and that's a lower number, eg 72 degrees instead of 73 degrees) puts the saddle roughly 10mm further back. 10mm is worth having if you are right at the end of the adjustment.
As to a source of information, I'm all out of ideas, at least of anything good.
For bike fitting, you could do worse than read everything you can find by Steve Hogg. For example his "sensitive issues" and "more sensitive issues" consider seat tube angle from the point of view of women on small frames.

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The utility cyclist
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Re: What should my next bike be?

Postby The utility cyclist » 13 Aug 2019, 10:06pm

I almost pulled the trigger on an Alchemy Helios carbon the other week, massively discounted (£1000 for frame and forks down from £3400), already have a really nice carbon but would have been a jump in quality if not that much in weight drop, I could afford it but just didn't need it, kinda regretted it but it's gone and I can still ride my fast bike and be happy.
Personally I would always but frame and fork and build up to the spec you want, that way there is nothing surplus and fits precisely to what you need.
On my carbon racer (unused ex cconti team KTM) the only stuff that matches brand wise are the STIs/chain/brakes, derailleurs and pedals. I have carbon Modolo bars, Cirrus 4ZA stem, carbon FSA cranks, carbon rithceylogic post, carbon rail Selle Italia saddle.
IMO having the carbon contact points at bars/saddle and post adds a little more comfort, not epic amounts but it's knocking off weight at the same time. I also use carbon Campag Bora One's tubulars, tyres are 27mm Veloflex vlaanderan and 25mm conti competition, I really think this combination is a good mix of low rolling resistance, comfort and reliability, I'm around 95kg atm but have been 107kg and ridden 22mm tubs in the past.
If you're going a smidge wider you don't need 28s, just make sure you have the pressures front to back correct and maybe buy some latex tubes presuming you're on clinchers.

Size/fit wise, I'm 5ft 11, monkey long arms and the KTM is a 59 (I also ride a 62cm traditional diamond frame as well) and even though the frame/forks are relatively heavy by modern standards the bike comes in under the UCI weight limit of 6.8kg with the pedals. I have a decent handling winter/audax/touring/utility bike, decent spec, rolls really nicely and just does everything very well, but riding that compared to the carbon racer is night and day even though the weight saving is less than 3kg.

Buy the best f&f you can afford, most modern carbon frames will take 28mm tyres these days, if you want a racier frame but want to avoid the lower down front end then you could go a size up, I've got diffy shoulders from rugby and a high speed off so I wanted a higher front end without having to resort to a steep angled stem so the 59 works well for me and I'm not overly stretched even with a 110mm stem as the TT is still a bit shorter than my winter job (which was a high end hybrid when I bought it).

Take your time, try plenty, spend wads of cash that makes you happy and want to continue riding as hard or as gentle as you want. :D