Tire opinions please, facts optional. | GTAMotorcycle.com

Tire opinions please, facts optional.

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inreb

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I have a useless to me sport/naked running the usual 120/70R-17 fr. and 170/60R-17 rear. I want to turn it into a gravel road runner and in the interest of protecting the "mags" (surprise pot holes) I hope to run 130/70B-17 and 160/70B-17 tires. I've already mounted a BT-45 rear tire to the front to check clearances and will be sourcing a BT-020 OEM for BMW K1200LT for the rear. This tire is way over built as it is for a touring barge. Rim widths all match. So basically, I'm running a rear in the front, going from radial to bias and changing sizes. What could go wrong?:cool:
 
Just put on a set of trail attacks and be done they will do all you need, unless you plan on doing singletrack with rock gardens.
 
Scuba Steve said:
Just put on a set of trail attacks and be done they will do all you need, unless you plan on doing singletrack with rock gardens.
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No, the trail attacks don't have 130/70 option. Not willing to go 130/80 on front. Almost impossible to get radial 130/70. Thanks for your opinion.
 
What size front tire are you putting on the back?
 
inreb said:
No, the trail attacks don't have 130/70 option. Not willing to go 130/80 on front. Almost impossible to get radial 130/70. Thanks for your opinion.
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How about a 120/90 on the front?
 
unL33T said:
How about a 120/90 on the front?
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Not recommended or safe with standard issue 3.5" wide sport bike wheel. 130/70 BT45 now mounted actually measures out to 137mm wide, clears fender and forks, plenty of meat to absorb pounding. It's locked in unless somebody comes up with good reasons to not use rear on front.
 
inreb said:
Not recommended or safe with standard issue 3.5" wide sport bike wheel. 130/70 BT45 now mounted actually measures out to 137mm wide, clears fender and forks, plenty of meat to absorb pounding. It's locked in unless somebody comes up with good reasons to not use rear on front.
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Aren't most stock front tires 120 wide?
 
unL33T said:
Aren't most stock front tires 120 wide?
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Yes but the aspect ratio factors into what rim width to use, generally. Taller tire, narrower rim seems to be the way it goes. Look at a tire fitment chart. It's dry reading but sure takes the guess work out. For example the label doesn't always match the actual measurement.
 
inreb said:
Yes but the aspect ratio factors into what rim width to use, generally. Taller tire, narrower rim seems to be the way it goes. Look at a tire fitment chart. It's dry reading but sure takes the guess work out. For example the label doesn't always match the actual measurement.
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I always figured rim width vs tire width was most important and not the height but guess I'm wrong. Is it the same for cars?
 
Yes sir.
 
How much of the pounding do tires actually absorb?

I always thought that we had suspension on bikes for a reason.
 
Is bias-ply construction more important than width? There are several 120/70B17 options.
 
Baggsy said:
How much of the pounding do tires actually absorb?

I always thought that we had suspension on bikes for a reason.
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Any time you see a dented rim I'd assume the tire was completely pinched at that spot. A beefier tire thru construction and/or size should mitigate that in theory. Serious off road bikes never have cast wheels.
 
Matt Rain said:
Is bias-ply construction more important than width? There are several 120/70B17 options.
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I believe bias ply side walls are stiffer. Could probably get away with 120/70B17 but liking the extra 130 meat. Also, as noted above, the BT45 is actually 137mm wide. It looks boss on the bike.
 
inreb said:
It's locked in unless somebody comes up with good reasons to not use rear on front.
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Quick google search result; Food for thought

"Rear motorcycle tires are responsible for certain bike functions, such as:
  • Power The rear tire has a flatter profile, to provide the majority of the acceleration and stability for your bike, and wouldn’t handle as well if put on the front.
  • Weight The rear tire carries the majority of the weight of the bike, calling for special design elements to keep you upright & safe at all times.
  • Lean Since the rear tire does not turn, it is subject to the lean of the motorcycle. This requires a sturdier tire with a flatter profile to accommodate this requirement.

Front motorcycle tires have specific characteristics, as well as limitations, including:
  • Braking The front tire provides up to 80% of the braking power for your motorcycle. It’s shaped to provide this, rather than acceleration like the rear tire
  • Turning The most obvious function of the front tire is turning right & left. A front tire is more triangular shaped for better handling. You would notice this if you were to try to put a rear tire on the front, as they aren’t shaped for turning and you’d have a hard time turning your bike properly.
  • Tread Because the front tire’s main purpose is braking, the tread isn’t going to be as thick. This would become very obvious if you were to run a front tire on the rear of your motorcycle. You would notice that the tread would wear down very quickly due to the thinner tread on a front-specific tire.

It is also very important that your tires be mounted in accordance with the manufacturer’s instructions for rotation direction. There is an arrow on the sidewall of each tire, indicating the proper direction of rotation. This is just as important as purchasing the correct front and rear tires, because the tires are shaped and weighted in accordance with the recommended rotation direction. It may be tempting to run a tire backward, but your tire will not only wear unevenly, your bike will not perform at its best if you are running a tire backward. The only exception to this rule is if a tire includes both directional arrows and is specifically marked as a dual-rotation tire"
 
^^ That's why I mentioned running them backwards when you switch sides in another thread. That's what Continental was recommending for the TCK80s before they had 17" fronts available.
 
Neil_V said:
Quick google search result; Food for thought

"Rear motorcycle tires are responsible for certain bike functions, such as:
  • Power The rear tire has a flatter profile, to provide the majority of the acceleration and stability for your bike, and wouldn’t handle as well if put on the front.
  • Weight The rear tire carries the majority of the weight of the bike, calling for special design elements to keep you upright & safe at all times.
  • Lean Since the rear tire does not turn, it is subject to the lean of the motorcycle. This requires a sturdier tire with a flatter profile to accommodate this requirement.

Front motorcycle tires have specific characteristics, as well as limitations, including:
  • Braking The front tire provides up to 80% of the braking power for your motorcycle. It’s shaped to provide this, rather than acceleration like the rear tire
  • Turning The most obvious function of the front tire is turning right & left. A front tire is more triangular shaped for better handling. You would notice this if you were to try to put a rear tire on the front, as they aren’t shaped for turning and you’d have a hard time turning your bike properly.
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That a flatter rear tire won't turn as well as the front only means it won't be a scalpel. I also don't see how braking would be unduly compromised by running a flatter profile on the front compared to a triangulated tire. That's counter intuitive. You know that fatty on the front of the DR650? That's a rear. It's not holding me back too much. Maybe ask Dougie:p

Neil_V said:
Avon Distanzia? Can get close to your desired sizes, and I would suspect the tire construction would be more capable of absorbing any unseen potholes etc. than your average sporty tire.

http://www.petes-superbike.com/distanzia-am43-am44-c-2234_1_3394_3415.html
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Awfully tempted to go 130/80 rear on front, some real gains to be had there with softened rake/trail but I feel 130/70 should be the first try(had a b/n sitting on a shelf anyway) and I can keep the stock fender.
 
inreb said:
That a flatter rear tire won't turn as well as the front only means it won't be a scalpel. I also don't see how braking would be unduly compromised by running a flatter profile on the front compared to a triangulated tire. That's counter intuitive. You know that fatty on the front of the DR650? That's a rear. It's not holding me back too much. Maybe ask Dougie:p
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More of a construction/sidewall thing than profile I suspect. That said, average riding, and dirt for that matter, it's probably not a huge issue.

P.S. Dougie's Rosso Corsa's probably lack the "Inreb trail rating" :cool:
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