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Numpty IM Bike Thread
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I,ll give it a go, Ta
silly questions?
Firstly,
Anyone know what I can do with my old campag 8spd mavic open 4 CD rimmed wheels - specifically, can these run 23mm or 25mm tyres ?
currently on 18mm michelin racing tyres bought when lemond hadn't quite retired. but brand spanking new 20yrs old tyres.
Secondly,
where can I source campag record 8spd cassette, chain, durallier jockey and chainrings ? ( going to need to replace them soon - and makes sense to go from 52/42 ( 12-21 ) to something more forgiving ie.52-38 or 12-28. ? )
thirdly,
replacing the quill stem / scott DH bars / chorus ergo with modern equivalents ( and maybe record ergo - the bike was from the year before they came onto market ). quill adaptor-deda anatomic bars-ergo from eBay- cables and tape
many thanks
PS Yes, its my original 12kg columbus slx campag 8spd workhorse that will suffice as training bike - its about time it had some use unless maintenance proves to be problematic
The rims would probably be OK with a 23mm tyre, but you might find you don't have enough clearance through the forks.
Campag 8 spd - wiggle have some cassettes, or look for Miche 8 speed ones which will work too. 8 speed chains are easy to find, with chainrings you might have a problem getting some with the right BCD - campag standards have changed over the years.
Replacing the quill can be done, either with an adaptor or replacing the forks altogether. Although I'd guess the head tube is 1" which would limit choices somewhat.
To be honest though, by the time you've forked out for components to match the original quality, you'd have spent enough to get a very decent training bike new. Unless you fancy the challenge of a restoration project (and why not?) then I'd be tempted to keep that one as a turbo bike and spend the cash on a new one.
Help needed
i was changing the cleats on my shoes and the top screw snapped leaving the thread in the shoe.
so what can I do if anything, will they be ok with just the 2 bottom screws or new shoes time
use a drill to remove the screw. ( drill out the snapped thread part or drill a hole(s) sufficient to insert a small screwdriver and gain purchase to remove. a bit of d40 ).
i anticipate you'd be ok, but the cleat would flex when climbing out of the saddle and that could screw your knees/ankle over time ( as you pull the foot up ) or suffer a mechanical failure resulting in nothing good.
i have found an old 8spd cog set in a box in the loft ( where it was left a couple of decades ago ) - just need to find the alignment guide to build the cassette alignment.
chainrings are problematic - some alternatives on eBay but i need to remove and measure and check.
chain is easy. as is quill stem etc. total cost looks around £100-150.
new bike would be my preference but if I did that, id rather a variant on the race bike to share parts ( carbon 11spd ultegra ) so 11spd 105 maybe. - not going to be £150 though.
You could try & drill the screw out, or get a bike shop to try it for you. Failing that, two screws will be fine most of the time if they're nice and tight, but you run the risk that at some point you'll twist your foot to get out and the cleat will stay where it is, so you can't release.
If you're happy the cleat is it the right position, you could use a decent quantity of araldite in place of the front screw. You won't be able to change the cleats again, but at least you won't run the risk of falling sideways at traffic lights.
Glad I found this thread, as I have a question that is almost insane in its bicycling numptiness ... in fact its not my question at all, I am asking on behalf of a friend you understand.
I ... err .. my friend that is, was wondering, if its best to get tucked down in to as aero position as possible going in to a head wind, does the same still apply when (in that all too rare occurrence) you actually manage to get a tail wind, or would it be better to sit up and benefit from a greater 'push' from the wind ?
If there's a honking tailwind then buy a lotto ticket that night and yes I'd sit up a bit and enjoy it.
If its only slight then I think you need to be a bit aero anyway.
I believe in Scandinavian countries cyclists have rigged up sails to make the most of tail winds - but that could be an urban myth.
With the wind directly behind, if your friend is cycling faster than the wind speed then the net effect is still a headwind, so best to be aero. If he's going slower, then sitting up would help. So if he's riding at 20mph, with a 15mph wind from behind, the net effect to him is a 5mph headwind. When he turns round and rides at the same speed into the wind, the air will be going past him at 25mph, so a lot more drag.
I'll attempt (probably get it wrong too) an answer at this, but I'm sure someone like the Engineer will come along and give a better physics lesson. Apologies if this derails into drivel!
The trouble with cycling is that you need to contend with both land speed and air speed. Land speed is the speed the bike travels over the ground (hopefully also with you attached). Air speed is the total of land speed + air speed opposite to the direction of travel.
examples:
You're going at land speed of 10mph into a headwind of 10mph. Airspeed is therefore 20mph.
You're going at land speed of 10mph with a tailwind of 10mph. Airspeed is therefore 0mph.
You're going at a land speed of 20mph with no wind. Airspeed is therefore 20mph.
So - why is airspeed important? Mainly because this is the main component of what determines the air resistance stopping you going any quicker (F=MVsquared from memory - meaning a very large force is required to overcome a very small increase in speed).
So lets for the sake of argument now ignore rolling resistance, bearing friction etc. and assume that all things being equal, on a day with no wind, you're capable of travelling at a land speed of 20mph before the resistance due to the wind becomes too much to go faster. This is basically saying that you're capable of overcoming an airspeed up to 20mph.
If we now go back to our examples, but keep the airspeed constant and look at what that does to landspeed:
Travelling with a 10mph headwind means a max landspeed of 10mph (airspeed 20mph)
Travelling with a 10mph tailwind means a max landspeed of 30mph. (airspeed 20mph)
Travelling with a 20mph headwind means a max landspeed of 0mph (will be very hard work! - airspeed 20mph)
Notice how in all the above, body position hasn't been mentioned. Body position will change the amount of resistance for a set airspeed. Tucking in will reduce the resistance (make you go quicker) and sitting up will increase the resistance. Lets say that the 20mph max airspeed was due to an upright riding position, and a tucked position would allow you to reach 30mph airspeed.
Our examples now become:
Travelling with a 10mph headwind means a max landspeed of 20mph (30mph airspeed)
Travelling with a 10mph tailwind means a max landspeed of 40mph (30mph airspeed)
Travelling with a 20mph headwind means a max landspeed of 10mph (30mph airspeed)
So in short - no, sitting up won't have any benefit, because you should still be pushing hard enough that there will still be an effective headwind - you'll just be travelling alot quicker in terms of land speed! If you were to sit up and stop pedalling, you'd get pushed along, yes, but at a much slower speed than you should be capable of.
tl;dr version - It doesn't get easier, you just go faster!
Wow! You could have done another training session in the time it took to write that
Good post though
Brilliant stuff, thanks DR .. I think I understood it (on about 4th reading
) ... so its aero (the term being used loosely here) all the way then !
I once asked a very good time triallist for advice on getting faster.
His sage words of advice were:-
"Get lower and pedal harder!" That is all....
ok, whats the likely cause ?
just finishing of rebuilding my travel bike. boardman alloy frame. ultra 6700 parts. all seconds.
fitted new bars and gear/brake cables. everything works ok without being on it.
BUT, when riding and specifically, when pushing the chin jumps of the big chain ring.
not when on the smaller chainring. - I think the rear slips occasionally also.
chain is near new. chainset is second hand - maybe its worn to much? could it be the big ring?
maybe the adjustment is out - chain length is good. needs tweaking a little for the rear maybe. front seems ok. just under load it slips pretty much every time of the big ring.
was able to clim out of the saddle on the smaller chain ring. can't do out with the big ring.
chain seems to be loose of the big ring. lots of side movement. but the same on the small ring
I had a similar problem a while ago, and it turned out that the problem was a stiff link in the chain that would cause it to jump at the back, but it only happened when I used the large chainring, probably because when I used the small ring the sharper turns through the rear mech sorted out the stiff link.
Otherwise, if it only happens when you're working hard, it might be that the frame is flexing and the front mech is pushing the chain off.
so, will lube and flex the chain. might be the front mech. setting it up was a bit of a ball buster.
its dropping of from a standing start. might be frame flex ? hope the frame isn't busted- can't see a sign of it.
another ride. any pushing on the big ring, at any point, on either side and the chain slips off. not even with a great amount of effort.
little ring is fine, all the rear is fine ( minor adjustment on the downpipes to the cable )
no flex in the frame I can sense - solid out of the saddle and over the 'pending repair' cobbled roads of Toddington area.
chain works fine on the little ring through the block - although if on the littlest front and rear the chain seems long ( rubs at the derallier )
potentially, a buggered outer ring - seems these are not cheap to replace either ? having someone take a look.
having the chain "large" at the front and "large" at the rear, or the other way round is call cross chaining, And the fastest way to knacker the chain and the block.
Any damage to the teeth on the cogs or is the large ring slightly bent? either could make the chain slip.
And the front mech isnt pushing it off ?
I've never seen that happen before.
Its not possible that the big ring is on the wrong way ? Outer face inward ?
I'd have thought tooth damage would be easy to spot.
Easy to spot ? This is Lard, he has only just learnt to recognise a bike.....
Turned out he'd managed to install them inside out.
hi
i was checking the chain for length, not riding it on the extreme. its slightly too long - a link only maybe.
cable has been reconnected tot he front mech on the inside and not on the outside ( which makes more sense in a picture - so picture the cable coming up wrapping on the inside of the nut and then out, rather than on the outside of the nut and wrapping in ) - its easier to change up/down now.
chain appears to have a twist on it for a couple of links. so obviously removing one of those might help. as would a new chain maybe
has slipped both ways - tends towards inside though. teeth on ring look fine ( worn but ). nothing missing, not bent. and I think it only fits one way - (ultegra 6750 compact 50T )
bike was easy to spot ( wheels, no rubber suit ) its the training I keep missing dave.????
Wrong chain ?
BB not in cockeyed is it ? Although I'm not even sure thats possible.
Bent axle thro the BB ?
I can see an 8 spd chain jumping off an 11 spd block, but don't see why it would jump off at the front ?
Is the chain sitting all the way down on the teeth of the big ring ?