Fast hybrid opinions ?

[PurpleFrog]

audax bike (700x25c) or touring bike 700x35c

Nuff said

Wrong. In fact, doubly wrong because you've applied bad logic to incorrect facts. With extra penalty points for applying Sheep Logic.

Logic: what people ride is marketing driven and availability limited, not engineering optimal. People see the TDF on TV, think fast bikes are 700c with tyres as narrow as possible for the load carried, aren't smart enough to do any research and 700c rims and tyres are easy to buy. Otoh, it was very hard to buy fast 26" road tyres until recently, and even now someone like you would probably buy the wrong tyre and conclude that 26ers are slower than 700c on the road.

Facts: the best of these bikes are 650b or smaller with +40mm tyres. (And often low trail.) For example this is Jan Heine's (he's a former holder of a NASA Fellowship and editor of Bicycle Quarterly, so he knows a little bit more about engineering than the average mamil or Internet bs-er applying "Everyone knows" logic):

http://www.cxmagazine.com/gravel-grinde ... k-360-2014

In fact, Heine isn't just someone NASA thought was a marvelous fluffy bunny, he's German. So tremble at the amount of OCD data gathering and experimentation that went into his wheel size choice.

Oh, and Thorn, who make excellent modern tourer/hybrids favour 26 and fat over 700c for a raft of reasons including overall performance.

Oh - and Audax bikes are a silly example because Audax bikes are aero enough (cough... drop bars) for tyre aero to matter more relative to rolling resistance in a way that it can't for flat bars. Which I did explain, but which obviously went over your head.

Useful graph for smarter readers:

..This is why it's smart to use tyres with poor RR but good aero on a dropbar bike you'll push at TDF speeds, but exactly wrong on a flat bar bike with its poor aerodynamics.

In fact, the big bike companies are acknowledging that now fast-but-fat rubber is available they need to introduce new fast bike designs - and the boutique buliders have been making them for a while:

http://www.bikeradar.com/gear/article/a ... umb-37270/

..They're generally 700c and fat though, because betting on the stupidity of the mass market ("Me see TDF ride 700c!") is usually smart. The only problem with 700c and fat rubber is that it makes for less agile handling due to gyroscopic effects and doesn't get you the rollover advantage on the road that 29ers do offroad... what with their being no rocks and roots to roll over.

So: flat bars with narrow clearance, just a bad design - one that is literally never right.

 

[pimpdriver]

Re:

I hope you feel smug having written that very long and comprehensive answer.

The OP was asking for opinions on "fast" not the "fastest", so a 700c audax bike would be fast. But as you spent ages typing, not the "fastest".

While you were typing I was outside in the fresh air with my bikes.

 

[The History Man]

So my GT is the fastest bike!



Should've kept it. My road bike is redundant unless I use the drops then. Which I don't.

A comprehensive and extremely informative explanation. Thank you mr frog.

 

[PurpleFrog]

Re:

It may or may not be. It's more correct to say that speed is the combined result of a complex interaction between rider power output, aerodynamics, and the tyre fitted (and its pressure). If you own a Zaskar with 50mm shaved Racing Ralphs (which for a long time was the main option for getting a fast high volume slick) and a Spesh Tarmac with 25mm Rubinos, then:

- Going for it on smooth tarmac, the Tarmac will smoke the Zaskar

- At a sane commute burn, the two will be much closer - because aero will be less important compared to rolling resistance, where they match

- If you put low drop bars on the Zaskar, then the Tarmac will still be ahead in the first case - but by very little; in the second case the difference will be minute

Now if you put the two on gravel, the Zaskar will smoke the Tarmac - because the 25mm will vibrate the rider's fleshy tissue like crazy and this is an energy sink. On the nastier sort of gravel even the flat bar Zaskar will take the Tarmac, but energy losses will be so high that the Tarmac won't be able to go fast enough for aero to matter.

But the Sirrus will always turn in a worst case performance. It has the aero of the Zaskar, and the nasty vibration losses of the Tarmac. So why bother? Well, except to sell bikes to people who think narrow tyres are fast, no reason at all.

This is why the people who know what they are doing and spend big money on tourers are buying 650b bikes with 40mm clearances and running tyres like Grand Bois - or Thorns with 26" wheels and clearances for 2.5" tyres. (Which lets you run 2.5 Big Apples; these aren't truly a fast tyre but the grip on the road is supposed to be insane: http://www.thorncycles.co.uk/forums/ind ... 798.0;wap2) The 650b crowd then get a bit weird because they believe you can't build chainstays for a high performance bike that allow wider tyres than 40mm - so they seem to have missed the 90s.

As for why people drop to the lower wheel size as they fat up: gyroscopic inertia makes fat tyre 29ers a pain to steer unless you wide bars, and these terrible for aero.

So the bikes that lots of people here have built - mtbs with drops - are seriously good designs and probably held back only by their tyres, because it's hard to find a fast but wide 26 slick. The new Schwalbe Almotion should be one solution (you can buy them at half the UK price from bike24 in Germany), the Super Moto another (but no puncture protection), and otherwise you can shave an MTB racing tyre:

http://bartthebikeman.wordpress.com/201 ... road-tyre/

..And the typical sports hybrid design is just awful. It's built to look right and nothing else. Well - awful is unfair; it's not like the narrow tyres will explode, they're just a limitation on performance that has no reason except marketing.

 

[PurpleFrog]

Oh - and the 650B boutique tourers are also low trail, because this gives them better handling with a load over the front wheel. They're a return to traditional French tourer design, so very retro - except for having brifters (and sometimes these aren't fitted) you can't tell the new $4000 bikes from ones made in the 50s. They seem to make a religion of avoiding a sloping top tube even they are meant to tour on gravel as well as tarmac, which seems just stupid to me and my sensitive bits. This is the cannonical bike, a '52 Renee Herse

..and this is a fancy that won't let me copy images for one of the new mass production tourers:

http://store.velo-orange.com/index.php/ ... mkiii.html

 

[stewlewis]

So what's the answer ?!?!
My opinions.

I've done 50M on these three, all of which were 2nd hand, built by me and didn't cost a great deal:

The Trek 1.2, flat bar road bike.
Fast, on tarmac. Would keep up with the mates, on tarmac.
A hard ride, sketchy on loose stuff, and I fell of it big stil on a greasy wet road.

The Dawes Discovery, hybrid hardtail.
Heavy, comfy, slow, can go for miles on it, feels steady.
Upgraded with Tiagra road size gearing. Hydro brakes, needed ?? I dunno, stop the heavier bike easily, feels good on the lever yes nice n smooth which makes for a nice ride.
The bike I've done the most miles on.

The Marin Point Reyes, 'Urban' Hybrid.
MTB geometry, 48T hybrid ring. Rigid yet light. 26" rims.
This bike is fast, fun, and steady. Feels like I can ride anything on it and is comfy.
I'll be doing this one up as a keeper.

 

[wookiee]

Re:

...like that Point Reyes looks good!

 

[widowmaker]

Re:

Any idea what the Marin weighs ?

 

[stewlewis]

As seen here, which was the last incarnation I had a weight for 11.2kg
I think around the time, '06, a mate had a Palisades Trail, which I'm sure was the same frame.

It's going to be my next paint project, I'm thinking vintage colours with leather and wood.....

 

[widowmaker]

Re:

11.2 thats not a bad weight.

I wonder if my Univega build will be near that