The Grifo XS is Challenge’s ‘summer’ tyre and by that we mean dry, hardpack conditions, which we only really ever see in the UK in the summer and very occasionally in early Autumn races, but others in more exotic locations get all year round. After our Preview of the tyres we set out to find out if that is all there is to this tyre?
It is one of the supplest tyres we have ever tested with a superb 300tpi casing. As a result it feels fast from the get go. The file tread and small side knobs don’t really suggest loads of grip but will also offer little rolling resistance over harder terrain, so this tyre flies along.
Interestingly we first used these tyres in the Summer and were pleasantly surprised at their speed and general performance. Then in the early Autumn when things were starting to get wet we attended some training sessions on decidedly wet grass with them and they surprised us again at how grippy and fast they were. As long as you can get your weight over the right part of the bike they hold a line remarkably well; until that is you unexpectedly reach the limit and in a flash are left eating that same wet grass!
Pavement (5 out of 5): This tyre is fast on pavement and will zip along at a fair old lick for a cross tyre. It’s right up there with wider road tyres but remember, this is a race tyre and wear is not going to be its forte after extended road usage. If you are using your cross bike year round – and you should be, we all certainly do – then these make great dry weather tyres for mixed road and off-road conditions. They also grip well when cornering on wet tarmac.
Hardpack and dry grass (5 out of 5): The Grifo XS is designed for hardpack and as with on tarmac, this is a fast tyre for these conditions. The small side knobs give enough grip in the turns and it never feels like letting go, unless the going gets really loose when again they can let go very suddenly. The supple casing gives a very smooth ride over rough sections, helping you maintain speed, and it’s speed which is the impression you are left with after riding the Grifo XS.
Wet grass (2 out of 5): The Grifo XS is a reasonably competent performer on wet grass and will cope well enough with damp conditions if the rider is familiar with where the limit is; I managed to find the limit quite often and the way the tyre lets go is shocking. It all happens so fast that you have no chance of saving it, especially with the front. On a mixed course, that’s mostly dry but with some sloppier bits, they cope well enough but once the track gets wet an intermediate would be faster and safer in the corners for most of us.
When new the white rubber is very white
Sodden grass and light mud (1 out of 5): The XS is getting out of his depth by this point. You can ride it but it’s going to be tough going, and given the extreme behaviour on the limit expect plenty of spills.
Mud (1 out of 5): Well it’s unlikely you’d ever end up on the Grifo XS in muddy conditions but if you did, you’d find it tough when the bike is in a straight line even with all your weight hanging over the back end of the bike and just plain scary when you try to go round a corner.
Snow and Ice: I am told that these tyres are good in icy conditions but having had such a mild winter, I have not had a chance to put this to the test; I will make a point of testing this next winter but with the warmth of the summer on it’s way as I write this, that’s not a priority with these racey hardpack tyres.
The Challenge Grifo XS is a very fast tyre. In the right conditions it flies. Its open tubular design, light overall weight (355g) and high thread count mean it is a great tyre on firm ground. However, you have to know the tyre well to get the best from it and this can only be done by practicing a lot; by that we mean practicing cornering over and over so you know where the limit is. That’s how you get fast on these tyres, otherwise you’ll be in for a few shocks when leaning into those bends…
The white rubber used on our pair is meant to be grippier than the black version but not having both back to back, we cannot verify that. However, it does look pimp – until it gets dirty that is, as it would seem that no matter how much you clean it, you cannot get back to the original, bright white shade after that!
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