time trial bike question

[Nob]

Yep lovely custom job with split seat tube & wheelbase of 35" which was a handful.

The gearing is 68x12-17 block I only used the 68 one time in a club event did a middling 23 on the U7 course in 83. Really hard to get it rolling....

The pic you will see is in semi strip down mode as the left hand crank is already removed & the stem is nearly removed.

 

[torqueless]

Re:

Yeah I was wondering about that stem.

I guestimate that frame had about 5mm of brake/tyre clearance?

 

[Midlife]

Someone mentioned Frame pricing, here's a scan from 1978 with example RRP pricing.... I'm still searching for a Viner / SABA

Shaun

 

[Nob]

Re:

One assumes you clocked the Saba frame on Hilary Stones Website :?:

 

[Midlife]

Yep, seen that one, priced at £195. It's in my size as well...................

Shaun

 

[benseddon]

I find 70's TT bikes fascinating as I used to race them but were a revolutionary dead end as we didn't think about aerodynamics much and we could lose more weight going to the toilet before a race than by fitting SABA replacement titanium seat bolts.

Shaun

I find the evolution of bike geometry fascinating. Like many people I started riding as a kid and that continued till I was about 17 and then my beloved Specialized A1 rockhoppa got stolen but by fortunate coincidence i passed my driving test and no longer needed a bike. I didn't get on a bike again till I was 32!!!!!

A lot happened has happened in the intervening years and bikes are completely different. Take a modern road bike that comes in either aero or lightweight format. When I was a kid they were just called Racers and all looked the same pretty much. They even looked like mountain bikes, albeit a little skinnier and more stretched out. Obviously since browsing the threads on this superb forum my knowledge has improved on the differences but my point is the overall shape of a bike didn't change much for a very long and then suddenly there are hybrids, lightweights, aero, 29er, hard tail, full sus..........I could go on. That's why I prefer retro bikes to new ones. I have a fairly new bike. Its a Carrera Vanquish and I picked it up second hand. Sure it's got my gears than my Falcon Majorca, and better wheels, it may or may not be lighter but you know what.....it's just not as fun.

 

[oonaff]

Re:

i dont get it ! why would they want to build a frame thats all nervous and not want to steer in a straight line by itself or do they come into their own at a certain speed ?
is the steep s tube to give the rider a type of 'running' over the pedal action ?
or was it just a trend because of different concepts of the time ?

 

[Nob]

Re:

 

[Midlife]

those cranks bring a smile to myself every time I see them............A triumph of style over physics. Which sort of sums up my 70's TT'ing days

Shaun

 

[torqueless]

Re: Re:

i dont get it ! why would they want to build a frame thats all nervous and not want to steer in a straight line by itself or do they come into their own at a certain speed ?
is the steep s tube to give the rider a type of 'running' over the pedal action ?
or was it just a trend because of different concepts of the time ?

Well, we've got at least two erstwhile testers here between your post and mine, which I never was- I'm just an afficionado of the metal, so if I get this wrong they can put me right...

I think the 'nervous' geometry was a side-effect 'cost' of pursuing the 'benefit' of keeping the weight down. All else being equal, a conventional frame with steep angles, short wheelbase and extreme close clearances is going to be lighter than one without. If you had a 70 degree seat tube you'd probably need 17 1/2" chainstays just to get the rear wheel in, so with 75 degrees you can use 16" chainstays and that's three inches of steel tube you don't have to lug up gradients. Same thing with the close clearances. Nob might tell us how short the chainstays were on his split seat-tube bike upthread if he remembers..

...Plus, before Thatcher and privatisation and all that, it was probably someone's job to keep the roads in repair without having to first under-bid a crowd of competitors for the contract by skimping on time, labour, and materials, so your 'nervous' bike had a fair chance of going in the direction you pointed it, and your 28 spoke wheels with 7-ounce tubulars had a chance to stay intact.