Wheel upgrade

Worthwhile?

61 to 75 of 75 messages
TheEngineer    pirate
27/06/2013 at 22:14
IronCat5 in the Hat wrote (see)
TheEngineer wrote (see)
Cheerful Dave wrote (see)
 
TheEngineer wrote (see)
WhizKid wrote (see)

This is a lot too process on a Friday evening engineer, but it makes for interesting especially the argument of weight vs aero, the main factor I would bring into that theory though is the riders ability, unless its a pure straight decline, but that is me being very nerdy 

I tend to see things in a very black and white world! On a descent speeds are generally higher (or you're going through brakes like inner tubes), so acceleration will be faster as a result of improved aerodynamics. Even if you're a nervous descender, you're still getting something out of it. Compare this with the difference of 200-300g in a bike + rider combination of 70kg+ going uphill, and you're onto a winner.

But using that same argument, the difference in drag between expensive and cheap wheels is small compared with the drag from a rider sitting up on a descent because he's a nervous nerys.

Yeah but you can change the wheels.

You can also zip up the man-suit and learn to descend. Cheaper* than new wheels.

*probably

Until it costs you a bike! Nearly binned the TT on Sa Calobra last month, it is so long you build confidence at a steady rate until you have a moment! As much as I love both, the TT is not the ideal bike for that road!!

Blisters    pirate
27/06/2013 at 23:00

Which reminds me.

The headset needs tightening. There's nothing like a bit of a front wheel shimmy at 40mph+ to add some excitement into your life.

Cheerful Dave    pirate
27/06/2013 at 23:26

You took a TT bike down Sa Calobra?  Chapeau.  Nuts, but chapeau.

Dustboy    pirate
27/06/2013 at 23:48

I just googled descent of Sa Calobra on bike. Engineer has cojones. Feck that!

And Chapeau!

Cheerful Dave    pirate
28/06/2013 at 07:42

The only reason for going down there is for the ride back up!

Darkness    pirate
28/06/2013 at 09:03

Michael Hutchinson's twitter feed contains a lot of interetsing stuff on aero vs weight etc. and there appears to be little doubt that for TT/triathlon bike legs aero trumps weight every time, hilly course or not. 

Road racing is different because you can draft which reduceds the aero benefit and there are numerous accelerations when weight really counts (compared to pushing out a steady speed).

The latest interesting nugget I got from him was that you really need to be careful about not running your chain at an angle by choosing to run big ring big cog rather than dropping onto the little ring due to the extra energy required to move the chain when it is being bent sideways - and that one is free!

 

   

Cheerful Dave    pirate
28/06/2013 at 10:28

That last one always seems obvious Mr D but you always see loads of people running big-big or small-small who seem to have forgotten that they have a front mech as well.

That's what happens when you only ever use your right hand, I suppose.

28/06/2013 at 11:46

All interesting reading but am still trying to figure out how I can know what will fit on an ancient 80s road bike. Yes I am completely binkers but you know.. Pirate (wannabe)

Blisters    pirate
28/06/2013 at 15:38

Ali, don't decry a 1980's frame just because of age. I've got a lovely frame made from double butted lightweight steel, and overall it weighs barely more than my aluminium framed road bike. The forks are a bit heavy though. The frame itself looks very thin by comparison with today's carbon and ali chunky things, and thin is good. The best way of checking fit is to go to a bike shop. There are some key measurements, and I may forget something:

-diameter- almost everything today is 700c, and this was becoming the standard in the 80s. My old bike is 26x1.75" and nothing fits!
-width - I'm not sure whether a modern 10 cog rear wheel will fit in the gap left by an 80s 5 cog rear mech. I think that it should do.
-chain size- these days your chain has got to be brand matched to your cogs, both front and back. A Shimano 7/8/9 speed cog block needs a chain to match, and the front cogs may (not sure here) need to match too. Certainly they would need to be Shimano.
-How they fit these great big stacks of cogs on the rear is to really dish the rear wheel , and they make the chain thinner. Then there's a 10 cog or 11 cog stack! The result is that people now snap chains during races.

Recommendation: Keep the old bike for when you get a winter training turbo. Ogle new bikes and start saving up for a 1 year old model. Just my view.

Cheerful Dave    pirate
28/06/2013 at 16:10
Blisters wrote (see)

-chain size- these days your chain has got to be brand matched to your cogs, both front and back. A Shimano 7/8/9 speed cog block needs a chain to match, and the front cogs may (not sure here) need to match too. Certainly they would need to be Shimano.


Not quite.  A 10 speed KMC chain will fit 10 speed campy, shim or sram and work just as well if not better than the own-brand ones. 

Chainrings (the cogs at the front) will work across brands provided they're matched to the right BCD (bolt circle diameter) which is basically how the bolts attaching the rings to the right crank are arranged - there are various BCDs depending on whether you have Shim or Campy, regular or compact.  But you could take a shimano chainset with shimano chainrings and it'll work fine with a campag chain.  My TT bike has an FSA chainset, shimano front mech (operated by a campag shifter), KMC chain, campag cassette & rear mech.  The engine is still the weak link. 

Blisters    pirate
28/06/2013 at 22:41

OK, I live and learn.

How about a simple version: A wheel designed for a campag block won't take a shimano or SRAM unless you use a VERY big hammer. That's true isn't it?

29/06/2013 at 06:30

If you have got a road bike and you want fast wheels but not deep rims Planet X have got Shimano RS80 C24  carbon wheels for sale at £339 they are not deep rim but are light fast as feck and climb like mountain goats I have had a pair on my roadie for 6 months now and they were significantly better than my old Promotes and they were not to shabby as wheels go, for the price they are a steal the rims are the same as the mega bucks Dura Ace equivalent

29/06/2013 at 06:34

Think your right on that one Blisters but some people seem to possess massive hammers

30/06/2013 at 20:04

Thanks Blisters, my frame and forks are double butted steel it's a Raleigh 531 frame and firks so not bad. Got shimano front chain set and and a sun tour ultra block behind. 700c wheels so that's OK but as you say fitting a modern wheel and hubs and finding a small enough rear block would be the tricky part. if I stick at it after Outlaw I think perhaps a new bike might be my next step. 

05/07/2013 at 00:01

Thanks everyone for the advice, especially IC5.

Ordered a pair of white Planet X AL30`s, a pair of Conti Ultra Sport Tyres (white also, should look the nuts) and a new cassette.  

 I`ll report back the (if) performance benefit of the change asap.

 


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