Telelevers

[vgcspares]

anyone else out there noted the propensity of these to shear off both stanchions and/or part out the top yoke during relatively low speed frontals ?

I seem to remember having seen half a dozen or more cases over the last year

[longwayfromhome]

I have ridden BMW's for the last 10 years, am a member of several very active BMW sites, none of them known for holding back on criticism of BMW or their products, and I have never heard this stated as an issue, concern or even as an observation. Interesting.

[vgcspares]

Ralph, it was just an observation born of the latest mangled wreck I've seen - 73kph impact into the boot of a car (which pulled out on the rider) - not a criticism of BMW per se, but I do find it odd that I've seen so many where something of this nature has happened

[Mystic13]

vgspares you're saying;

Relatively low speed frontal = 73kmph...?

I wouldn't call that relatively low speed. Or if I did what would be high speed?

[vgcspares]

I guess I'm saying conventional forks appear to bend rather than shear off at that speed, which is only 45 MPH and therefore not huge

strewth eventhough Harleys will crumple their forks in almost any frontal impact, they don't seem to have the front wheel go bobbing off with such gay abandon

[longwayfromhome]

Vgspares...thats OK, I know you weren't criticizing per se. Thinking about it, maybe the telelever would potentially "shear" the front forks more often than standard forks, for two reasons:
1. The force of the crash is spread over a greater length of fork in standard forks, with the telelever being braced at about the 2/5th's of the way down the forks, which makes them much more rigid fore/aft than standard forks.
2. I suspect standard forks are stronger because they carry both the wheel/steering forces and the suspension components/forces, whereas a telelever carries only wheel/steering forces.

You do imply this is a problem from your observation...do you mean shear right off, or give a hard fold in the forks? In a head-on with the wheel pushed back towards the engine, with the lower fulcrum point on the telelever, the wheel travels proportionally further in an arc around the fulcrum. This would potentiate shearing forces....but I am not a materials engineer....just an observation. There again, you would tend to have more damage on regular forks to the main head area....yokes/bearings etc.

But, to be fair, and to go back to the original post, I haven't seen any mention of losing the front wheel completely as such a regular occurance as to excite any comments.

I personally think the telelever is safer in a head-on because the front of the bike and rider are not dipped down when the front brakes are on...the more upright attitude is safer.

BTW, I recently extensively rode the Duolever-equiped K1300GT. I thought telever'd bikes were great, this bike is a work of genius for sports touring and touring. It would have the same "issues" as the telever'd bikes.

[Pixie]

2. I suspect standard forks are stronger because they carry both the wheel/steering forces and the suspension components/forces, whereas a telelever carries only wheel/steering forces.

.

Both types are built to withstand the highest force a bike feeds into it's chassis-the deceleration under brakes.

Alloy doesn't bend much,it cracks,so telelevers and duolevers will break.
Telescopic forks have a steel stanchion which will bend rather than break.