just a brief burst of info before the next 'proper' post. grab yourself a copy of the current issue of singletrack magazine (issue 19) which has five pages about a singletrack visit to islay when the weather was so bad, they never even made it offroad (or very many other places either). really good article and great plug for islay
a work around
after the previous post about single speed hubs and wheels and anything vaguely related to both, we're still on the hoop track this time round. firstly, apologies for the enormous delay in getting this post onto the web, but i was away at the beginning of january and, well you know how it is…
as i have probably mentioned ad nauseam, i have a fancy for building bicycle wheels - seven hundreds, bmx, mtb, it doesn't really matter - a wheel is a wheel is a wheel. however, when i started doing this way back when, the bit i coudn't figure out was what length of spokes i needed to buy in order to build a successful wheel.
the clever books, such as those by jobst brandt and gerd schraner will cheerfully quote the mathematiccal formula required to figure it out, always assuming that you know the exact diameter of the hub flange and the rim itself. and if you're really keen (like i was) you will immediately spend ludicrous amounts of money on a copy of sutherlands manual where there is a complete set of charts relating to various rims and hubs to give just what you need without looking out the scientific calculator.
only there is a downside. i bought my copy of sutherland's in the ealry nineties and, with one or two exceptions, most of the rims mentioned in its hallowed pages are no longer made, or they've been upgraded. and if you phone your (or my) friendly cycle wholesaler who tells you that he doesn't have that model in stock, but they've just received a delivery from another rim manufacturer and the new stock is similar to the previous, would you like to take those instead? so having figured out the spoke length required for the original rims and having placed that order, you are now going to take delivery of rims from another manufacturer which may, or may not, be the same diameter as the ones you had planned to order, but you can't tell because they're not even listed in your ten year old copy of sutherlands.
so what's a guy to do? because you should remember that wheels destined for multiple gear systems have to be dished. this means that, to leave room for the alarming number of sprockets on the drive side of the wheel, the spokes have to lie 'flatter' (in the case of ten speed transmissions, they are almost perpendicular) than those on the non drive side which don't have to make space for anything. this means that the spokes on the drive side actually require to be a couple of millimetres shorter than their counterparts. or do they?
in computer terms, what i'm about to describe would probably be regarded as 'hacking'. for an individual or even more so, a very small cycle repair shop such as my own, it doesn't make a lot of economic sense to stock separate sized spokes for each side of a rear wheel, bearing in mind that wholesalers sell boxes of one hundred, not sixteen or eighteen. after building a few wheels, you gradually get to know roughly what length of spokes is required for what type of wheel: 36 hole mtb hubs built three cross on 'standard' mountain bike rims are roughly 264mm. shift down to the increasingly more common 32 hole, still three cross and we're into 268mm. 700c standard rims (something like a mavic ma3) built three cross work out at 296 or 297mm - the more aero style rims go down to about 294, or if building four cross, we move up to 301/302mm.
it is perfectly possible to use the same length spokes on both sides of the rear wheel, though you'll find that more of the spoke shows through the inside of the spoke nipple on the drive side than the non drive side. to this end, you should always build with box section 'double skinned' rims, though in practice, i've never found anywhere that sells the extruded 'u' shape to bike shops. the reason you need to build with box section rims is that any spoke showing through the nipple, is still too short to get anywhere near the rim tape and, subsequently, a very highly inflated inner tube or tubular (in the case of 700c wheels).
granted, there are a finite number of threads at the end of the spoke and if the spoke really is too long, you'll run out of threads well before the spoke is anywhere tight enough to build a decent wheel. so while the manuals stress one spoke length for drive side and another for non drive, it's not that desperate a problem. front wheels have no dish so spokes are the same length on both sides, generally the same length as the non drive side at the rear.
so if you fancy taking the plunge and having a go at building your own wheels, don't be put off by all the fancy numbers and formulas. i've just completed a rear 700c using a drc (really good italian rims) similar in profile to a mavic open 4cd and built it four cross using 302mm dtswiss spokes. granted, 301 or 300 would have been just that wee bit better, but out of all the spokes i have sitting in the bike shed, the choice was 296 sapim which were just a fraction too short to build three cross and the 302 dt which were a tad longer than i'd like but still laced and trued into a nice sturdy wheel. four cross is generally regarded as overkill these days, but the fact that it builds almost vertically opposite spokes as opposed to the tangential spoking that results from three cross, it's a better bet for heavy riders, or folks ho hammer their bikes a bit more than the average.
next option is whether to use the method shown in barnetts cycle manual or gerd schraner's method. the latter completes one side of a wheel before embarking upon the other, while the former builds the heads out spokes both sides before adding the heads in both sides. schraner's gives you a better idea sooner as to whether you've chosen the correct spoke length but it does make it harder to incorporate the last set of spokes on the second side because they have to be negotiated above/below/behind the ones you've just laced on the first side. barnett's method is structurally easier to do, but when you get to the last few spokes and they won;t quite reach the spoke nipples, you discover that either you've laced it wrong, or you've used the wrong length of spoke. and believe me, if you find it hard lacing a wheel, it's a damn nuisance having to take it all apart again.
by the way, i've already had promises of photos for the velo club d'ardbeg web page, so just a reminder: if you've bought an ardbeg cycle jersey, get a photo of yourself wearing it along with your favourite bike, and we'll put them up on a vcd'a page on the post, before we start hassling the good folks at ardbeg to incorporate similar onto their own website. and remember, the official tea stop and club hut is at the old kiln cafe at ardbeg distillery. wear your jersey anytime you visit.
rss stands for really simple syndication. what it means is that, when i update the post, i set up a brief description of what i've written, and using a newsfeed reader (on the mac, newsfan is a good one) you can be alerted when a new post is on the server complete with a link to take you there. if you're on the darkside (windows) try using newsgator
set your newsreaders to check http://www.ileach.co.uk/post/rss/index.xml and every time you scan the rss feeds, it'll tell you if there's anything new.
if you missed the ardbeg cycle jerseys, click here for a look see.
i had an e-mail from john houston of falkirk bicycle club whom i met a few years back cycling (he was) on a whisky/cycle trip to the island. since john has been gracious enough to link to the post, i am reciprocating. www.Falkirkbc.co.uk
this website got its name because scotland's graeme obree built his championship winning 'old faithful' using bits from a defunct washing machine.
on a slightly different note, my regular reader will have noted the addition of a 'colnago c40' rollover to the left. this contains a reprint of a recent article featured in cycle sport magazine, which they were very kind to let me present here (because i'm a colnago geek) there are also links to cycling weekly reviews of the colnago c50 and colnago dream b-stay. i have also found an excellent review of the colnago c40hp here
i have been asked to add the following link to the post by wheelygoodcause. they're a cycling club dedicated to arranging epic rides for charity and do not charge charities for the pleasure. They ride because they want to. here's the link.
Remember, you can still read the review of 'the dancing chain' the utterly excellent book on the history of the derailleur bicycle by clicking here
as always, if you have any comments on this nonsense, please feel free to e-mail and thanks for reading.