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| Continental's Grand Prix tyres are fast, but don't like high speed cornering and braking. |
The main problem, I think, is that they are simply not intended for use on a fast tricycle like the Mango. Sideways forces, especially when braking, are too much for them. On a two-wheeler it isn't possible to put such a sideways force on a tyre, nor to brake with a considerable sideways force on the front wheels without instantly falling off. The rubber was lost right outside our home, as I rode in quickly. A touch on the brakes, the wheel on the inside of the turn was in a skid, and there was a smell of rubber.
Even if I'd not had this problem, I was already planning to replace the tyres. Both Grand-Prix tyres already had cuts in them presumely due to small stones or pieces of glass (I didn't find the cause). This all happened a bit too soon for a practical tyre.
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| I'm now trying their SportContact tyres instead. Hopefully these will stand up better to everyday use. |
The advertised weight for the SportContact in this size is 295 g, however mine were actually a little lighter at about 270 and 280 g each.
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| New tyres fitted and ready to go, on a cycle path wide enough that riding an unusual bike is never a problem. |
The maximum pressure stated on the side-wall on the SportContact is 6 bar ( 85 psi ), but the accompanying paperwork attached to the tyre says 7 bar ( 102 psi ). I'm using the higher pressure. I have suspension so don't need the tyres to contribute too much to comfort, and they'll roll faster at the higher pressure.
My rear tyre remains a Schwalbe Marathon Racer. This still barely looks run-in. Actually, it wouldn't have been a bad choice for the front wheels as well.
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| Visit our webshop for practical, genuinely useful parts of all types for all bicycles. Including fast hard wearing tyres for recumbents and velomobiles. |
Tyres and tubes and other nice stuff can be bought at our webshop.
13 comments:
I find myself wondering (as I design a yet-again-improved dynamo-driven electrical system, this one perhaps good enough to build) how long it will be before someone deploys reliable ABS for bicycles. There is one described in Bicycling Science, tested to fork destruction even, but somehow it has never seen the light of day.
Why would you not run Marathon racers in the front?
I have marathon racers on my bike - the front has done over 10000km with no punctures, and the rear did 7000km with only 2 punctures. For a relatively light tyre, I am really impressed.
@dr 2: There is already ABS on bikes: To discover it, get in a car with ABS and go down a steep hill. Now cut the engine and pull out the fuses on the brake assist circuit...
OK, sorry, just kidding of course, the problem with ABS on bikes is more philosophical than technical. A bike is simple. ABS is not.
@David: Maybe if you still have problems with these Contis you can see if they will develop a special "David Hembrow Edition" tyre that will match your needs :-)
I've been using Conti Travel Contact on Bristol's streets for some years, with virtually no punctures and good longevity. The side-wall reflectors are great too, try taking a flash photo of your tyres in the dark and you'll see what I mean. Recommended.
". . .ABS for bicycles. . . it has never seen the light of day."
Perhaps because it is a solution looking for a problem.
Might make some sense in a pedal by wire system (of questionable sense in and of itself), but you'd still want purely mechanical backup.
The paraboloid-esque profile of bicycle tyres isn't really ideal fortri/quad/etc cycle applications where the cycle does not lean to at all/to the same degree. What would be a good idea is if a company made square profile (car-like) tyres designed for tri/quad/etc cycles
Yes! The Square, a.k.a. as "The Hembrow"! ;-)
Actually, there have been attempts at making square section tyres for velomobiles. Vredestein made one, but then everyone decided they didn't like it much so it didn't sell well (it's not a bad tyre at all, just not an exciting one - neither especially fast nor especially durable). Schwalbe are supposed to be producing something special about now. I've not seen the result yet.
Oh, and as for why not Marathon Racers on the front ? Actually, that's a very good question. Perhaps the best answer is "just because". I felt I would like to try something which is potentially a little sportier. However, if the sensible me gets in charge then I'll probably end up with Marathon Racers all around, as they're a very fine choice.
"square profile (car-like) tyres"
These are actually made. However, they are necessarily heavy (try to make a square balloon and you'll quickly see why), have high rolling resistance and require camber neutral suspension systems to actually derive any particular benefit from them (even at fairly low cornering forces the carcass deforms enough to "peel" the tread from the surface). They also introduce the possibility of hydroplaning.
And there's really no problem with round profile tires on HPVs that can't be addressed with carcass construction and rubber compound.
Are they good on a rainy road?
I've only had damp roads so far, and have not ridden them in pouring down rain. Also, we're kept away from the worst of conditions here. However, no problem so far.
I do know what it can be like. The Tioga Comp Pool and Avocet Fasgrip Carbon 12 tyres are my reference for dreadful behaviour in the wet. Both of these are lethal on any damp surface.
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