Monday, September 22, 2014

THE TOURING TECHIE : A guide to advanced biking

A Guide to Advanced Biking - Tips Tricks and Misconceptions



I have been riding the NS all over India and beyond, just like a dirt bike still nothing happened to the rims. Infact, I like taking it through the bad patches more. Its actually the technique that comes into play here which causes the damage or saves it... I will explain it a bit here and are only applicable for the alloy rims..

If you are riding and suddenly see a pot hole, try to reduce speed as much as possible before you reach the pot hole. If you are still braking while going into the pot hole, you will definitely be braking while coming out. The main pressure that's applied on the walls of the rim are when the tire strikes the edge of the pot hole. If your tire pressure is above 35psi (note: heat expands the air in tire resulting higher pressure) you are actually riding on tires with a pressure of approx 40psi. Such high air pressure will not act as a padding, rather will pass the force to the rim walls by enhancing it 1.5 times. The force applied to the walls would be the speed you are at + the depth/height of the wall multiplied by the force you are applying on brakes. At this strength, the walls of nearly any alloy will develop at least a minimal crack.

1. Don't fill air more than 25-30psi
2. Reduce speed as much as possible before you reach the pothole.
3. Do not apply brakes while going in or while exiting the pot hole.
4. While exiting the pot hole, a very minimal acceleration would be beneficial
5. Stand up on the foot pegs while going through the pot hole/pot hole infected region (Don't try if you are not confident enough of your bike).
6. Fatter the tire and heavier the bike, rider and pillion, more the force of impact.
7. Don't apply hard braking while going though a pot hole infected area. It will do more damage than any good. Apply engine braking.

Exactly same rules govern the case of spoke wheels but the difference is that of the outcome. Tubes generally blasts in cases of blunt force applied at 90degrees and any other angle results would be the rim bends and breaking of spokes additionally.

Courtesy : Internet

Upgrading your stock tire configuration that comes with say 130/70-17 to a wider tire involves much more than you can possibly imagine. To begin with, there are 2 types of tires namely Radial and Bias. Hoping that you can make out the basics from the image,  I will jump straight to the advanced part.

1. Physics 101: Mass expands on heating. So does tire.
2. There is no multipurpose tire. An off road spec will have issues on tarmac and the same goes with street spec running on off roads.
Courtesy: Internet
3. Wide tires are specifically seasoned for tarmac/track usage. Using it on off roads will have its share of lessened tire life.
4. Rubbers Expire. So does your tire. Change is very much recommended after 3 years. Post 4th year of its manufactured date, its as good as useless and will be dangerous to use.
5. Bias and Radials have their own set of pros and cons. Bias are load bearing tires, Radials are lighter & faster.
6. Every bit of rubber embossing on your tire mean something. Manufacturer did not write its advertisements on them.
7. Tire has 5 components, namely Bead, Carcass, Sheard, Tread and Sidewall.
8. You absolutely do not get soft compound tires to use in street. The ones you get are Hard, Semi-Hard, Medium and Medium-Soft.
9. Tread blocks need compatible counter tires. Unmatched treads will cause problems are hard corners.
10. Manufacturer is smarter than consumer. Its not at all easy to surpass their expertise these days.
11. It is definitely not a very bright idea to downsize the speed rating of tire than the manufacturer's suggestion.
12. Tire weight and air pressure does play an effective role in mileage, handling and stability.

When you are touring, you generally tend to cover long distances without stopping. This causes the tire to heat up. Generally it is advised to use Nitrogen rather than normal air which contains around 75% of nitrogen. Additionally, high speed touring on Radial is much better than using Bias. If you want to use wide tires just for looks, make sure that there is enough room for the tire when it expands. It can expand till 30% of its size under normal riding usage.

Tires come in various compounds. You definitely do not get 'Soft' compound tires in the market for normal/street usage. Even if you manage to steal one from your-friend-who-races I would certainly advise you against installing that no matter how great a Stoner or Rossi you may be. Soft tires are ONLY for TARMAC made with TAR and not CONCRETE and definitely without any DUST or SLUSH or POTHOLES on them. Harder compounds are less grippy and more resistant to punctures compared to the soft compounds. Even maintaining the bit-more-than-adequate amount of tire pressure also helps in less punctures and higher mileage. If you maintain 40psi of pressure to a manufacturer standard of 28psi you will end up with a 14% of excess mileage but with a lot less tire grip. It will also result in rims to crack in case you happen to cross over a pot hole.

Tires with manufacturer spec air pressure is more preferable when doing off-roading. Bias based tires are generally used for off roading and for carrying loads. It is never advisable to ride these tires with more than the manufacturer's spec of air pressure. Try and be slow on these tires and take breaks for cooling off. Over heating will result in a tire blast much easier than the Radials. These even weigh a tad more than Radials.

As already mentioned, Radials are high speed capable and are lighter. A medium compound radial with a-tad-more-than-adequate air pressure with Slime is practically invincible on street touring. Tires come with Speed rating i.e. the max speed class the tire can handle effectively. One would be in danger if that speed rating is crossed along with everyone around him.

Stability is a factor much influenced by tires. It depends on the front and rear tread blocks being compatible. Secondly, the tire should not be up-sized more than 3 sizes above the manufacturer's standard i.e. if your manufacturer say 130/70R-17 which means you can at max deviate till 150/70R-17. Up-sizing more than that will cause problems. Always make sure that there is free space available for the expanded tire. Difference caused by up-sizing.

Another factor that influences stability is the excessive unbalanced weight of the front vs rear tire. While up-sizing do keep in mind that the fatter the tire, the heavier it will be. Difference of more than 86% of tire weight (front vs rear) will cause instability and difference of more than -17% weight (rear vs front) will cause instability at high speeds, apart from the fact that it will be a hard challenge to reach high speeds in the first place.