This month’s Star Letter writer thinks that our practice of putting the same tyres on all test bikes is a bit unfair. Here’s why we do it.

A question of control

I’m sure you have been asked this before but when you do a back-to-back test, is it really fair to swap the OEM tyres for a control tyre? I can imagine the bike designer arguing that they supplied the best tyres for the job and that the suspension is designed as a whole with the tyres. Also, anyone who has saved their last penny to buy the best bike they can afford will not want to immediately swap the tyres. I think you should ‘ride as supplied.’

– Julian Wiseman

Ed – It’s a really valid question, one we’ve wrestled with for decades. First up,suspension systems are designed around wheels sizes and tyre width ranges, but not specific models. Secondly, tyres make such a huge difference to a bike’s ability to corner, brake, jump or accelerate that it’s vital we test them all the same contact point and a level playing field. There is an exception to this, which we’ll get to shortly.

This control tyre then [Maxxis High Roller II] let’s us see which bikes are truly performing well — but were perhaps hampered by a cheap tyre to keep costs low — and which bikes are relying on superior tyres to generate grip. We think it would be unfair not to swap the tyres. It also takes away one of the variables when it comes to measuring geometry – BB heights particularly are influenced by different tyres.

You’re right when you say those who have saved every penny won’t want to fork out for new tyres, but most good retailers will happily swap tyres for you at point of purchase and only charge the difference.

We also don’t swap out the tyres on bikes that cost less than £1,000 because the tyre is such a large percentage of the cost of the bike. When the price goes beyond that though, we think it’s reasonable to create a level playing field. Hope that answers your question, Julian. Have a lovely jacket on us for asking such a great question.

Contact us: mbr@timeinc.com

All Star Letter correspondents win a Madison Zenith waterproof jacket worth £99.99.