splike virgin

I need some advice on xc spikes.  I'm doing a race on Saturday in Richmond Park so I'm expecting a lot of mud/ snow.  I've done a couple of xc races before but always in my normal running shoes.  This time decided to treat myself to a pair of xc spikes.  The question is- what length of spikes should I use?  The shoes I got came with 5mm ones but the guy in the shop told me I would be better off with 9mm.  Does it largely depend on the surface you run on?  Which ones would be best for my race?  I don't think there are any gravelled sections on this one but every race is different.  Should I change the spikes depending on the race?

Advice much appreciated!

Not a stupid question at all, it's the very question I ask myself evey time I turn up on a Saturday afternoon, with four different length spikes to choose from! 

5mm is very short, you'd use those on the track.  9mm is still relatively short but would be fine on soft or firm grass if not too muddy, and you'd even get away with gravelly sections.  If it's going to be significantly muddy then 12 or 15 would be more suitable, but only if you've got soft surfaces (mud/grass) all the way round.  If there is fresh snow, you'd also want longer spikes in for a bit of purchase.

It's something that you will learn to judge with practice & experience. As Philpub says quite possibly up to 15mm in muddy conditions or in snow - I always think my spikes look terrifying like that - they could do someone some serious damage if used as a weapon!

The thing to watch out for is if the ground is frozen when you will need to go much shorter.

Bast advice I can give is buy a few packs of different lengths. Get there early & look at the course and try a few different lengths out to see what will be best. Don't forget though that, especially if it is a multi-lap race (as XC usually are) then by the time everyone has been round a few times it is going to be considerably more churned up than at first, so perhaps go one length longer than you'd think.