Perfect fit: getting a bike made to measure

It’s all coming together. The Viner Maxima RS road bike that we’ll eventually be reviewing on road.cc, that is. The made-to-measure carbon frame has just been crafted in Italy and we’re getting pretty excited about slinging a leg over the finished bike.

If you visit road.cc regularly – and if you don’t, what the hell are you doing with your life? – you might remember that I was measured up for a super high-end Viner a few weeks back by bike fit specialists Velo Solutions. Read all about it here.

Briefly, for the late-comers at the back and the hard of remembering, Guiseppe adjusted the fit on my current bike in a short session at Le Beau Velo in Shoreditch, London – all perfectly painless, I can assure you. Once he was happy that everything was absolutely spot on, he measured it up and tapped all the details into the computer, and that was that for a few days.

Then, ping! A couple of designs arrived in my inbox. Guiseppe had been away, done the calculations – probably scratched his head, whistled through his teeth, and spoke to himself in Italian, I’m guessing – and come up with two different designs based on the bike fit we’d done: a ‘sportif’ option, and a ‘race’ option.

Most of the key dimensions were identical. The distance between the bottom bracket and the top of the saddle, for example, was the same across the two designs, as was the overall reach to the bars. The main difference between them was that the top tube on the race design was a centimetre shorter than on the sportif design. This meant that the wheel base, the distance between the two hub axles, was a touch shorter too, which tends to make a bike more manoeuvrable.

In order to compensate for the shorter top tube and get the reach the same, the race design had a longer stem – which slows the steering and adds a bit of stability. There was a small difference in the head angle too and a tiny difference in the amount of trail. Trail, if you don’t know, is the distance from the middle of the front tyre/road contact point and the point where an extended line drawn straight through the centre of the head tube hits the ground.

Anyway, let’s cut to the chase: I opted for the race design, chose the stealthiest finish known to man, and fired my email back to Velo Solutions in double-quick time. They sent the chosen design over to Viner who cracked on with the manufacturing process...

Believe it or not, the carbon tubes that Viner use for the Maxima are produced to the specific requirements of each customer. In other words, there’s no stock pre-manufactured tubeset. The tubes are made to suit the size, weight or potential power of each rider. Crikey! When they say they tailor these frames, they really mean it.

The frame builder cuts the tubes to the correct length, mitring them to the specific angles required, and then puts them onto the jig – called the ‘mask’ – which has been set up for the size and geometry of the frame. The mask is actually a technical bit of kit. Digitally controlled, it ensures that everything is made to within 0.1mm/0.1° of the design spec. It’s a high-tech business.

The next step is to bond the frame tubes together with an epoxy resin that Viner have developed. This just keeps the tubes in place so the frame can be removed from the mask for the proper jointing to be done. Once the resin is on, the frame is part cured in the autoclave – a high pressure oven, essentially – to set correctly, and then it can be taken off the mask. At this stage it’s already looking a lot like a bike frame.

A bit like Look and Learn, this. Okay, so the tubes are in place. Next up, it’s time to make the compression joints – the permanent joints that have to hold the tubes in place when you’re hurtling downhill at 50mph. You want this done right, and Viner employ specialist staff for the job… which is reassuring.

These wrappers first cut individual sections of pre-preg carbon fibre (carbon fibre cloth that has already been impregnated with resin) to the correct shape, then build the lugs making sure there’s no contamination between the different layers. Guess how many pieces of carbon they use: up to 150 on one frame.

Once they’re done, the compression joints are wrapped in compression tape and the internal sections of the frame are filled with a silica sand to stop them getting crushed when the frame is put back into the autoclave. The frame then goes into a vacuum sac ready for curing.

Viner have developed their own curing process and the details are secret. It’s all very hush-hush, the old frame building game. What we do know is that they put the frame into the autoclave that uses a balance of internal and external atmospheric pressure and temperature curves to mould the individual layers of carbon into solid sections of carbon and resin. The new joint is highly compressed with ultra low voids, which means there’s an even mixture of resin and carbon with no micro air bubbles in there.

Then they take the frame out of the autoclave, let it cool, and it’s ready to be hand finished. The compression joints can be made to be smooth and invisible or the frame can be left with a visible lug appearance. They check the frame is still in perfect alignment and track, fit any accessories that have been requested, and it’s sent off to be painted.

And that’s where we’re at. Our Viner Maxima RS frame has been lovingly hand-crafted, had its lick of paint, and the next step is to get it assembled. We’ve got an exciting plan for that in the new year, which were not going to tell you about just in case we curse it. Watch this space.

Contacts

• Viner www.viner.it
• Velo Solutions www.velosolutions.eu
• Le Beau Velo www.lebeauvelo.co.uk