TIRES -> SPRINGS -> BEST USED BIKES -> CAMS
Bridgestone's S2U, designed for improved wet and dry traction, features soft-compound side tread for better cornering grip. Or does it?
Q: I ride a 2005 Suzuki SV1000S and recently installed a stock-size Bridgestone S20 dual-compound rear tire. After 75 very easy miles, I noticed little rubber balls (like you might see at a track day) on either side of the center of the tread. So, I grabbed my trusty durometer and tested it. The hardness is 50 in the center two inches and 60 on the outboard tread sections—exactly backward from what I would expect. The durometer pattern remains, cold or hot. To verify my findings,
I took the durometer to the local bike shop and saw that all the dual-compound tires there had softer tread compounds outboard of center, as expected.
So, did I get a bad tire? My riding style is very slow and cautious, but I like the feel of performance tires more than that of touring tires, hence my choice. The tire feels fine while riding, but I don’t want to push lean limits with this tire.
CHRISTOPHER 0. CUNEO
A: Based on your durometer testing, it definitely seems that you got an improperly manufactured tire. No
one produces tires with soft-compound rubber in the middle and hard on the edges. That would defeat the very purpose of dualcompound technology and cause the center to wear out rapidly while leaving plenty of not-as-grippy tread on the sides.
I spoke with the U.S. head of engineering at Bridgestone, who insisted that the company had no knowledge of any such compound mixup. Obviously, he was extremely anxious to examine your tire in an effort to figure out the full extent of the problem and how it might have occurred.
To that end, I have already sent you his contact information, and he has arranged to get your tire in his possession and replace it with a properly formulated new one.
Even after he inspects the suspect tire, he may have to send it for further evaluation to Japan, where all Bridgestone motorcycle tires are designed and manufactured.
Since tire companies do not make tires one at a time, it is entirely possible—even likely, actually—that other riders also have an S20 tire with this same compound discrepancy. If anyone finds this to be the case, they should first contact us here at
Cycle World, and we will ensure that the matter is turned over to the appropriate parties at Bridgestone.
REFEREEING A DEBATE
Q: I have a Honda VTXi8ooR with 127,000 miles. It has Progressive Suspension's progressive springs
in front and 440 shocks in the rear. Is it possible that this upgraded suspension is able to help tone down the effect of a blast of side wind better than the standard suspension? The answer would help settle a heated discussion with a riding buddy of mine.
H. DAN MARTIN
SUBMITTED VIA WWW.CYCLEWORLD.COM
A: The answer is no. The only exception would be if your VTX’s stock suspension was so clapped-
out (a distinct possibility, given the bike’s high mileage) that almost any disturbance, from the front, side or otherwise, might noticeably upset the chassis. But with the Honda's OEM suspension in reasonable operating condition, the difference would be nil.
Q: I have a Honda 2005 VTX1300S. If I installed a Voyager kit on the bike,
would the engine be straining to
pull it? Would it wear out the rear tire more quickly or decrease gas mileage? What are all the negatives to this conversion?
RON FRECEAU LANCASTER, CALIFORNIA
For readers who might not be aware,
^ the Voyager (www.mtcvoyager.com)
^ is a bolt-on kit that adds two nonpowered wheels at the rear; the bike’s original rear wheel continues to drive the machine
COT A MECHANICAL OR TECHNICAL PROBLEM with your beloved ride? Perhaps we can help. Contact us at firstname.lastname@example.org with your questions. We cannot guarantee a reply to every inquiry.
as always. The kit also is designed to permit a small amount of lean rather than always holding the bike perfectly upright like a trike.
Yes, there are negatives to such a modification. The converted machine will be heavier, taking its toll in acceleration and fuel mileage, as well as tire life —and not just on the rear. The front tire will wear more rapidly because the VTX’s steering geometry is designed for leaning while turning, not for remaining almost vertical. The tire will therefore “scrub” slightly in the turns rather than just rolling, accelerating wear. To what degree these factors will be affected depends on how you ride.
But there are positives, besides the obvious stability provided by a “four-wheeler.” Even though a Voyager conversion adds weight, owners report that they usually can stop more confidently and in shorter distances because they don’t have to worry about maintaining balance while braking hard. Plus, the kit requires no permanent modifications and is easy to remove, allowing the host bike to be ridden conventionally.
TIMING ÍS EVERYTHING
I’m hoping you can help me solve a conundrum. I have a Yamaha FZ6,
* and when you consult the repair manual about retiming the cams after replacing adjustment shims, it all seems fairly simple: Just line up the marks and off you go.
I also have a Benelli Tornado, and herein lies the confusion. Although ostensibly, the Tornado’s manual describes the same procedure, including realigning all the timing marks, it goes on to prescribe rechecking with special tools (three dial gauges, a topdead-center gauge and a goniometer), and then adjusting the timing by shifting the cam sprockets as needed in the elongated slots where they bolt to the camshafts.
Perhaps I’m being naive, but surely, if you time the cams the same as they were, you haven't changed anything that would need to be readjusted (apart from the offending shims). Could you please shed a little light on this confusion?
NORTH YORKSHIRE. ENGLAND
A0 use Some slotted manufacturers cam sprockets occasionally that allow B small variations in cam timing. In certain cases, this is done to ensure that the timing can be adjusted to precisely the desired specification, giving a technician the ability to compensate for any possible “stack-up” of manufacturing tolerances. It also allows the timing to be adjusted to help offset minor stretch in the timing chain.
And some companies use slotted sprockets to permit small cam-timing variations so they can use the same components on different models or even use the same
sprockets with different camshafts.
I was unable to contact anyone at Benelli who could explain the service manual’s instructions. So, I can only assume that following the directions would ensure that the timing will be absolutely correct, especially in the event that one or both of the cams is being replaced during the adjustment procedure. With non-slotted sprockets, cam timing is not an issue if the marks are aligned; with slotted sprockets, it can be.
SHORT-TERM BRAKING TEST
Your Long-Term Wrap-Up of the BMWK1600GTL (March) says you * had to replace the rear pads because of aggressive riding at only 5468 miles. Either the brakes on the Beemer are terrible or your rider is bad. I’ve ridden aggressively since i960 and never worn out back brakes. A good rider uses the engine and brakes for best stopping power. So, was it bad brakes or bad rider?
ST AUGUSTINE. FLORIDA
AB The Story GTL's author brakes Mark are Hoyer linked, replies: so the u rear brake is always in use when slowing. Further, fully loaded two-up weight was about 1250 lb. Use of the rear brake on such a big, fast, heavy motorcycle is essential for short stopping distances.