Saturday, June 16, 2007

KTM vs Suzuki: 125cc GP racer vs 1000cc superbike…?


Small, but perfectly former. All muscle, no fat...

We are big fans of MotoGP here at Faster and Faster, and you see MotoGP-related posts here very often. But talk about 125cc motorcycle GP racing, and with us, you draw a blank. We admit we don’t follow 125cc racing, and we hardly know anything at all about those bikes and the men who race them.

But are we missing something? We thought it would be interesting to take a quick look at a 125cc racebike’s specs and see how, as a package, one of these machines would stack up to a modern-day 1000cc road-going superbike. Let’s take the KTM 125 racer, for example. The bike is powered by a single-cylinder, liquid-cooled, two-stroke 125cc engine that makes 55 horsepower at 13,000rpm, and 31Nm of torque at 12,800rpm. No fuel injection here – the bike uses a Keihin carburetor.


The Gixxer weighs twice as much as the 125 racebike, but is also three times as powerful!

The minimum weight limit (bike+rider) in the 125cc class is 136kg, so the KTM 125 racer probably weighs just 80 kilos! The twin-spar chassis is made of aluminium, suspension is Öhlins front and rear, brakes are by Brembo, wheels are lightweight Marchesini units and the gearbox is a six-speed unit. Fuel capacity is 13 litres, which means the bike probably averages about 10 – 11km/l during races.

On to, say, a Suzuki GSX-R1000 now. The engine is a 999cc, four-stroke, liquid-cooled inline-four, and depending on who you talk to (or which motorcycle mag roadtest you choose to believe), it makes anywhere between 165 – 180 horsepower at 12,000rpm. Top speed is close to 300km/h, and while we don’t really know the exact top speed of the KTM 125, we don’t suppose it would be more than 220km/h. The Suzuki’s 1:1 power-to-weight ratio also compares favourably with the KTM’s 1:1.45.


In the end, it could all come down to skill and experience. Kevin Schwantz on a GSX-R1000 should be able to take on any 125 racer. We hope... :-)

The GSX-R1000 is about twice as heavy as the KTM 125, but also packs three times the power. So the numbers at least are weighted in favour of litre-class superbikes. How would things be in the real world? Would an average rider who weighs 85 kilos, riding a GSX-R1000, be able to keep up with a 55kg professional racer, on a 125cc GP racebike, on a set of mountain twisties?

Would the 125’s agility and higher corner speeds (?) offset the Gixxer’s sheer power, acceleration and higher top speeds? What if the GSX-R was fitted with high-spec street rubber, while the KTM ran racing slicks? We'd love to find out, but for that, we'll need a KTM 125 racer and a 2007 Suzuki GSX-R1000. Anyone willing to lend us these two machines for a day…? :-D

Other great battles:
Fifth Gear video: Ducati 1098 vs Lamborghini Gallardo Superleggera!
MotoGP: Rossi vs Capirossi at Mugello!
Superbikes vs police helicopters!
Drag racing: Kawasaki ZZR1400 vs Suzuki Hayabusa!
Helmet wars: Snell vs ECE22
1988 Kawasaki Ninja ZX-10 vs modern-day Ninja ZX-10R!
Honda CBR1000RR Fireblade vs Honda Civic Type-R!
Acceleration: Supercars vs superbikes!

6 comments:

Bram said...

Just compare lap times.
E.g. take the benchmark motorcycle circuit: Assen.
In 2007, the fastest 125cc qualifier was Pesek at 1:43.370 with 215.870 km/h.
In Superstock racing on Assen, Corti did 1:42.773 at 275,1 km/h

Although this looks like a win for the 1000 4stroke, in a race the 125cc would win because it will draft on the straight, and win in the corners.

Anonymous said...

if you've ever ridden a 125GP bike you'd know that very rarely do ya have to tap the brakes. 125's are more fun to ride the corner speed you can carry is amazing and the bike flicks anywhere you want at anytime. they do take quite a bit more skill to master, because the only place to make time is in the turns. 125's are the true pinnacle of riding.

Anonymous said...

Anonymous is dead on, though you do have to break pretty hard on the little buggers!! Bram is a little off on a couple counts. The 125 would lose the battle cuz they will never be able to draft a big bike, 1 sec a lap is huge and the bigger bikes would slow the 125 in the corners too much if they started to dice.

Anonymous said...

A 250 superkart would be the one to bet on,2 stroke.They are as fast as rossi at assen at faster than any bike on the fastest track thruxton.Cadwell park they are seconds faster tna superbikes on gp circuit.They must be good rossi races them

Anonymous said...

A couple of corrections:

KTM rc125 weighs 66kg (has to carry ballast to meet rules)

Top speed. 240 km/h

Alot of track records (especially tighter club circuits) are still held by 125cc gp machines.

While the superbike may have a better power/weight ratio it has a higher centre of gravity which leeds to lifting the front wheel.

Cornering speed is determined by Absolute weight, not relative weight. I regularly go around the outside of litre bikes through the corners on my TZ125. This is on a club spec bike with a relatively untalented club rider on board.

Quick world-level 125 riders would qualify on the back of a moto gp grid.

No real comparison

Anonymous said...

The liter bike with a talented rider would on most tracks control the race and prevent the 125's from fully exploiting their advantages. On short demanding tracks the 125's would have a very good chance of pulling off a win with the proper rules in effect to give them a fair shot. That's my 2c worth.