You are here

Steering Safety

My new P-38 came with a steering riser held onto an adapter quill by a standard 1-bolt seatpost clamp. The clamp itself was affixed to the riser by virtue of having been sprayed over with black powdercoat paint.

There are some safety and design issues with this arrangement. First safety: It's a poor idea to have your life depend on a single bolt. Due to installation problems, my bolt sheared while I was tightening it. If it had sheared while I was riding, it would have caused a serious accident.

I have since re-seated the adapter quill so that it is all the way down in the steerer. (I didn't realize there was an adapter quill there or that it was part way out of the steerer. To get the riser height right for me, I had the riser all the way down on the headset nut, which meant that I was tightening the clamp below the wide part of the adapter, and over-stressing the bolt.)

I have also replaced the clamp with a dual-bolt 1 1/4" clamp from Power On Cycling:

poweroncycling.com/product/poc-stem-clamp-459.htm

I recommend that all Lightning riders with 1-bolt riser clamps do the same.

Now for the design issue. Using an adapter and quill is old-school and adds weight to the bike, and unnecessary slip-surfaces to the steering. Why can't Lightning cut the steerer a few inches above the headset and clamp the riser DIRECTLY ONTO THE STEERER (with a 2-bolt clamp) like a modern DF road bike?

I think it would improve safety, reduce cost, and save weight.

I am confused by your description, but maybe that is because I have not had enough coffee today.

On my older Lightning P-38 bikes, the threaded fork steerer tube extends up a little bit above the headset lock nut, and the steerer tube has a slot cut into it. The handlebar / riser /stem is inserted inside the slotted fork steerer tube, and is secured with a seatpost clamp. The slot cut into the fork steerer tube allows it to compress and grip the stem when the seatpost clamp is tightened down.

The riser is a hollow aluminum tube, with what appears to be a solid machined aluminum piece that functions as a stem inserted into the bottom. I think the solid aluminum stem part is secured to the hollow riser with Locktite or some similar adhesive.

As long as you do not try to honk on the handlebar / riser / stem, the old arrangement seems to work out OK. I guess that if you really pulled hard on the handlebars, you might break them. If this happened while riding, it could spoil your whole day. But I have never heard of this happening to any Lightning rider. It is true that the seatpost clamp only has a single bolt, and if that bolt breaks, you could be SOL. The single bolt does look pretty beefy though, and until your post I have not heard of failures before.

But you are right that a seatpost clamp with two bolts would be safer.

I do not have a clear idea of how your bike is built, but it sounds like it is different from mine. My apologies for being so dense.

Anybody else out there who can shed some light on Pitaman's description and criticism?

Safe riding,
Joel

Joel,
I don't understand your set-up either. With mine, the steerer tube does not protrude above the headset locknut. The slot is cut into the riser so that it can be clamped around an adapter. The adapter converts the 1" diameter of the steerer tube to the 1 1/8" diameter of the riser. The adapter quill looks like an old fashioned aluminum stem. It is inserted into the steerer and tightened by turning a bolt that runs through the length of the adapter and pulls on a friction wedge. The riser is then inserted over the adapter and tightened with a (now 2-bolt) clamp.

I think that I understand how your bike is put together now. Or at least more than I did before.

Maybe the adapter quill piece is used to give you a greater range of adjustment up and down than is possible with the older quill-less arrangement? Just a wild-ass guess on my part.

I imagine it would weigh somewhat more than the older style though.

I would send an email to Tim Brummer asking why he did this. He must have had some good reason. Please tell us what he tells you.

Safe riding,
Joel

If you scroll down the Lightning Riders home page, you will see that the Woodside J-Dart Pro and the Easy Racers Aptera both use 2-bolt riser clamps.

The quill provides a diameter match: the steerer tube is 1" o.d., and the riser is 1 1/8" i.d. I'll give Tim a try on this. I assume that one contacts him through the Lightning website.

Hey Pitaman,

Thinking about the seatpost clamp issue: are two smaller bolts really more safe than one beefy bolt? I don't know. Consider that seatpost clamps - both one bolt and two - are designed to support most of seated body weight of an upright bike rider resting on a traditional bike saddle.

To do this, it has to have much more clamping force and at least as much reliability as the clamp used on the Lightning steering system.

If Tim Brummer sheds some light on this, please report back and share with us.

Safe riding,
Joel

Tim said that he would consider the two-bolt clamp. Two bolts are not necessarily stronger than one, but that is not the point. The point is that the two bolts are not likely to fail at the same time, so that if one goes, you still have steering and can stop for repairs.

Tim rejected the idea of a modern clamping system without the quill, because he would have to redesign the lock-down tilt-down steering adapters as well, and probably has an inventory of them to sell first.

I may hack the bike someday with a different fork. But for now it's time to put on some miles.

Decided to use a Schwalbe Durano on the back wheel, since that's what I've got on the front. The bike handles more confidently, including (sigh) today in the rain.

I'd be more concerned with the means with which the quill is secured within the fork stem than the single pinch bolt. My first (suspended) P38 steer tube (quill) came adrift while underway. It was apparently secured with an industrial adhesive which became unsecured rendering me euphemistically rudderless at speed. I installed the more conventional bolt and jam nut quill with no further dramatics. The pinch bolt was never an issue. I am currently trusting the bolt and adhesive on my latest P38. .......... ScreaminDave

My directionally unpredictable P38's epoxy-like headlock was still intact when it went renegade. It was obviously not intact with the wider double bolt seat clamp and held forsome time. Both times myself or my mechanic friend talked to Tim or Brian they were asking about an internal device that might need a screw adjustment??? 2001ish bike

I get exactly what you're saying. I have issue with this set-up as well and so do my P38 riding friends. One that I know of has gone to the 2-bolt system for safety sake. It should be standard on all P38's, inspite of what Tim says about one bolt holding as strong as two. That's not the point. It's a critical clamp that needs a back-up and 2 bolts is the answer. All other short wheel base manufacturers' get it, why doesn't Lightning. I will be making the modification myself before next years riding season.
In my opinion, and I've voiced this before, why can't lighting go to a 1 1/8" headset like every other bike manufacturer. It would be stronger and increase your options if someone wants to change to a higher end or lighter headset.

Navigation

User login

Powered by Drupal