Units 1&2 Baruch Park

Viro Crescent, Stikland

021 910 0535

sales@mhm-mc.co.za

Mon - Fri: 9:00 - 17:30

Sat - 9:00 - 13:00

Pressures

The subject for today is tires, or more specifically tire pressures, I know, boring, but it could save you money, so let’s see how much I can waffle on. The idea was spawned, and I use that word deliberately, by my Cagiva V Raptor, pictured below or above. This is another one of my interesting motorcycles, hardly any in SA, I only know of one other and mine is decidedly not standard.

The Raptor 1000 was produced by Cagiva between 2000 and 2005 in three variants. Standard Raptor, Cagiva frame, suspension, bodywork with a 1000cc Suzuki TL motor, and Brembo brakes. V-Raptor like the standard bike but with straighter, lower bars, 7bhp extra, carbon cans and a small wacky fairing. Then the Xtra-Raptor same as V-Raptor but with lashings of carbon fibre and superior Marzocchi suspension, different rear linkage, and a steering damper. Created to compete with the Ducati Monster, the motor was torquey, quick, and reliable, possibly better than the Ducati’s, but the suspension struggled to contain it and this, along with Cagiva’s uncertain future doomed it to a shortish production life. Like Ducati, Cagiva also produced a smaller 650cc version, again using a Suzuki 650 V Twin motor.

I’ve got the V-Raptor, the one with the horns and claws, take a close look at the exhaust hangers. When I acquired it, the original red paint had already been changed to flip tone purple, the wheels sprayed white, the rear mudguard removed and short, very loud, cans in replace the originals. So, rather than return to original, I decided to go ever further, sprayed everything other than the frame black, wrapped the exhaust, changed a lot of the body work to carbon fibre, straight bars, airbox upgrade and, of course, lots of shiny gold alloy bits.

Ok, back to tires, small light frame, short wheelbase, and low steering angle should enable the Raptor to flip from side to side without any effort, mine didn’t, it did handle ok and was stable, but required, instead of just thinking about, actual effort to get it to turn in. Now I had a similar issue with my BMW R1200S but attributed that to the BM’s unusual Telelever front suspension, that is until I had to replace the tires because of ware, wow, new tires, and much improved turn in. Based upon that experience I assumed I needed new tires for the Raptor and showed then to Gino for advice on what to buy, he looks at them and says, ‘don’t need new tires try pumping them up’. Now I am very pedantic about tire pressures and frequently check them, so rather peeved I reply, ‘they are at the recommended pressure, 2.2bar front and 2.5bar rear, I checked’, well sort of, my real words were not quite that elegant. ‘No, no you misunderstand me’ say Gino, ‘pump them up more than the recommended, try 2.5 in the front and 2.8 rear’ again the real words not so elegant. So, I did, and guess what, no more effort, I just think, and the bike turns, brilliant and zero cost.

As I said earlier that experience got me thinking about tires and, sorry for stating the obvious, how important they are to how a bike rides and feels. If that 1 to 2 cm square patch of tire on road is not correct then regardless of suspension setting or fancy new sky hook, Ducati speak, electronic type suspension systems the bike is not going to handle at its full potential and that translates into less enjoyment for the rider. We get bikes coming into the shop, with tires 0.5bar to 1bar under inflated, not sure how the owners ride them, the front end is very heavy and imprecise, totally ruining the handling and feel of the bike. Worse still it’s dangerous, I recently rescued an elderly biker who had toppled off his BMW 100RT at a stop street, turned out the front tire was half flat and the heaviness of the steering cause him to lose balance and fall, fortunately with no damage to either him or the bike.

So, to conclude, check your tire pressures frequently, when I started riding on the road a wise old biker, and old is the key word here, advised me to check tires, pressure, and condition, at least once a week, very out of character, I stuck with that advise.  A good standard is 2.2bar front and 2.5bar rear for solo riding but check the manufactures recommended pressures, online if you don’t have the manual, then if the bike still does not feel good go up a couple, as in two, tens of a bar at a time until, as they say, improvement is felt. I have a Gold Wing that needed 3bar in the rear to correct a low-speed front end shake, despite Honda stating the rear should be 2.6bar. Two points of caution here, first don’t go above 3.5bar, if the there is still a problem at that pressure, then it’s something other than tire pressure. Second, it could be interpreted that the simple solution is to run the tires at high pressure but will cause them to wear unevenly in the middle shortening the life of the tire, the tire needs to be at the right pressure for a particular bike tire manufacture combination, and often this can only be found by a bit of trial and error.

Well, 900 plus words of tire pressure waffle, if you got this far well done, and thank you. Lastly, off road riders, if you had read this without giving up in disgust, please ignore all the above as your requirements are completely different.  ~ Bob

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