Numpty IM Bike Thread

Bike ponces only welcome if they don't speak in tongues

11,481 to 11,500 of 12,017 messages
27/03/2012 at 13:12
punctures are usually more frequent after the hedges have been flailed so spring or autumn are always the worst times.

I'm slowly building a 2nd MTB and will go with tubeless this time from scratch. Stan's No Tubes now also sell their own specced wheels (ZTR) which I'll go with (see what the price is like first). you can however use standard rims
Edited: 27/03/2012 at 13:13
TheEngineer    pirate
28/03/2012 at 10:09
I'm in the first flushes of romance with my adamo. This means I've got a sore arse, but at least I've not lost any feeling in the important areas!

Is it normal for the saddle or seatpost to creak a bit at first? New bike creaks intermittently but only when sat down - I think it's the seatpost...
28/03/2012 at 11:30
Seen a few mentions on here of TT bikes giving an average 3mph speed gain. Unless i've screwed-up the maths, that kind of gain would take 45 mins off my bike time, which gets me sub-12 for Outlaw. I'm a fairly flexi bloke and can stay aero on my roadie for long durations (granted the positions not so stressful as on a TT). But I wonder, is 3mph average realistic/common? And I'm talking about the sort of TT bike you can get from somewhere like PX for £1,500 rather than some serious bling. Any thoughts????
28/03/2012 at 11:41
I would think 3kph rather than 3mph

it's not just the bike though but the setup, wheels, training, kit (aero helmet etc) - and you and your buiuld. sure, TT bikes are designed to be quicker than a road bike but I don't think you can take a general speed gain as being a given.

I was having this discussion last night with the owner of my local tri shop (big Cervelo seller) and we both agree that TT bikes are fine for some people but they aren't the panacea to speed gain for all. if you're built like a brick shithouse like me, then 80% of my wind resistance is me, plus weight factor, and no amount of aero bike will give a big speed gain - incremental yes, but nothing major. I'm better off improving the engine and dropping the weight
28/03/2012 at 13:48

Hi All,

 Got a couple of numpty questions RE Valve extensions on Zipps.

For Mallorca HIM, I'll be taking spare tube etc in case of puncture. My numpty questions are this ...

1. How do you release air through the extensions ? 

2. When fitting the extensions originally, you need to open the valve and put insulating tape around the thingy-me-jig to keep the valve open. If I had to replace my tube during the race with the new one, would it be necessary to do the same thing with the tape i.e. bring tape with me on the bike during race ?

Sorry, I know I probably don't deserve my lovely wheels.

Thanks

28/03/2012 at 14:46
you've started wrongly - you don't need to tape the valve open - it stays shut even when unscrewed and will only release air when depressed. and with extenders you need to leave it open to inflate as needed. if you need to deflate the tube for some reason, stick a cocktail stick/narrow screwdriver or similar up the extension to depress the valve.

you should use plumbers tape (PTFE tape) around the valve screw (where the cap normally screws on) to get a good seal between the valve and the extension - that's what the taping is all about. pretape any spare tubes in advance so you don't need to carry any with you.

and if you've punctured you won't need to release air - the puncture's done it for you....

as an alternative use tubes with removable valve cores and an extension you can screw this into - that moves the valve to end of the extension and you can then handle it normally. it means you need to change valves and extensions but it's an alternative to consider.


and yes - you don't deserve the Zipps but enjoy them....
Edited: 28/03/2012 at 14:48
28/03/2012 at 15:28

Cheers FB.

 I did follow the instructions came with the extensions so guess I've done it right but just described it wrong

Thanks for the advice RE pretaping the new tubes. Didn't think of that. Makes, erm, perfect sense !

28/03/2012 at 15:36
ok - basics right, poor description, you're off the hook...
28/03/2012 at 16:15

Hi All,

 Got a couple of numpty questions RE Valve extensions on Zipps.

For Mallorca HIM, I'll be taking spare tube etc in case of puncture. My numpty questions are this ...

1. How do you release air through the extensions ? 

2. When fitting the extensions originally, you need to open the valve and put insulating tape around the thingy-me-jig to keep the valve open. If I had to replace my tube during the race with the new one, would it be necessary to do the same thing with the tape i.e. bring tape with me on the bike during race ?

Sorry, I know I probably don't deserve my lovely wheels.

Thanks

28/03/2012 at 16:17
fat buddha wrote (see)
ok - basics right, poor description, you're off the hook...

This is the 'numpty' thread. Should be a sort of amnesty, right ?
PSC    pirate
28/03/2012 at 16:55
it is the numpty thread don't panic.  All numpty's welcome and the only questions that are genuinely stupid ones are the ones that you don't ask. 
31/03/2012 at 13:38
Bit of a long shot maybe but anyone live near Brixham/torbay could recommend a spin class - going down there next week and fancy doing a couple of sessions just to tick over.
31/03/2012 at 17:57
I'll make an enquiry Pops of someone who does live that way!
Cheerful Dave    pirate
31/03/2012 at 20:10
Celt6776 wrote (see)
2. When fitting the extensions originally, you need to open the valve and put insulating tape around the thingy-me-jig to keep the valve open.

The reason they do that is not to keep the valve open (the tyre pressure keeps the valve closed as FB says), but to stop the little screw nut working its way back closed while you're riding.  If that happened you wouldn't be able to get any air in the tyre without taking it off the rim.  Unlikely to be a problem during a ride (unless you're trying to use a sealant inflator after a flat) but you won't be able to top up the air before the next ride - some tubular tyres don't hold pressure for very long.  Vittoria Evo Corsa, I'm looking at you.

Not that I've known that happen - I prefer the type that FB mentions using a removable core.  The only snag with that is that you really need to get your spares set up beforehand, extensions and all, but it does mean the valve is always outside the rim.

IronCat5    pirate
01/04/2012 at 20:55

Update: Barse now bedding in, and I find it a lot easier to ride the TT bike long distances. Happy bunny.

Numpty question #187070775:

What can cause the back of the bike to start wagging and it feel like I have a puncture. As the bike curves round bends it almost feels like the tyre is being rolled off the rim, or the wheel is bending? I've had this twice this week, both on long rides, and both whilst going very fast (so I assume descending - today certainly was).

Tyres were topped up before I left. Front to 80psi, rear to 90. Rear was close to 85 when I got back. As I was descending I can imagine there wasn't too much weight on the rear wheel. I did try and push back on the saddle, but it kep going until I slowed down.

Any ideas?

Also - does anyone else wander all over the road on their TT bike; is this something that defines us as triathletes? I do seem to get blown around a lot.

02/04/2012 at 10:06
C5 - I would suggest that you up the psi in the tyres. you're no heavyweight I know but you'd be better running them at 100-110psi (front and rear). what tyres are you running out of interest??

I'd also check your spoke tension as if they are a bit slack that could contribute to the feeling you're getting. you can tension them yourself or if you're not happy with that, get the LBS to do it.

and TT bikes do tend to wander a bit more - usually pilot error (you have less overall control whilst aero), or due to crosswinds affecting deep rims (if you're running them)

02/04/2012 at 13:59

Fell off my bike whilst stationary yesterday. Not for the first time . Was trying to open a gate and just plopped over sideways onto my right side (the gear mech side). An hour or so later when changing down onto the small chain ring for a hill, the rear mech snagged in the spokes of the rear wheel, dropping the chain and un-seating rider for a second time.

How likely do you reckon it is that the impact of the first bump has pushed the rear gubbins inwards and got it too close to the spokes? And if that's the case, any suggestions for how to shove it back out again without doing more harm than good?

02/04/2012 at 14:14
stil - sounds like the rear mech has been bent in enough to impact the spokes when in the lowest gear. I suspect the mech hanger's not been bent by much and you should be able to bend it back yourself BUT you need to be very careful when doing so.

first off - check you have a replaceable rear mech hanger - the bit where the mech bolts to the frame - it should be easy to see if it's replaceable or not as that bit will screwed to the frame. if it's not - get the LBS to sort it as they will be more experienced. the last thing you want to do is snap the non-replaceable rear hanger!!

next check where the bend is - chances are it's the hanger that's bent. if the cage (the bit that holds the jockey wheels) is bent, then you'll need to replace that.

as for doing it yourself, you need to be able to provide sufficient force to bend the hanger unit back to straight - and do so slowly rather than overstress matters. it's really down to feel I suppose and then the difficult part is getting the unit straight.

unbolt the mech from the frame after removing the chain and using a good length adjustable spanner, tighten the adjustable onto the hanger and then SLOWLY bend the hanger back. a long handled spanner will allow more force and more "feel" for what you're doing. you may need to play around a bit to make sure it's straight (you can get a tool for this but for a one-off job, eyesight is usually fine)

but if in ANY doubt get the LBS to sweat it for you.

next time - fall the other way....
Edited: 02/04/2012 at 14:25
02/04/2012 at 14:18
Thanks, as always, FB. Off to the workshop with a coffee and a lump hammer .
02/04/2012 at 14:27
have another read - I've made some amendments
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