a safety issue?

[brider]

When you sit in your Silvio, the stem is pointing right at you, and is really quite high--so high that I wonder what would happen in a front-end crash. If one crashed into a pretty solid object like a car or tree at some moderate or higher speed, your arms wouldn't have enough strength to hold your body on the seat, and your body would come forward. It would seem inevitable that you'd get the stem right into your sternum, or even more scarily, into your neck. On many "conventional" recumbents, the handlebars are lower, and are positioned so the stem is in front of, and about even with, the knees. That seems safer to me. I wonder if, with a different handlebar design, something similar could be done with the Silvio? By eliminating the front-tube extension and adjuster to which the stem presently mounts, some weight could perhaps be saved as well. I'd be interested to hear what Jim Parker thinks given that he's a physician.

Thanks to all, and happy Cruzing!

 

[John Tolhurst]

Two things will probably happen if your have a serious head on.
1) front telescoping tube will collapse, absorbing impact and spreading the deacelleration over at least a few inches which has a very big effect on reducing the severity of the impact
2) bike and body will rotate up about the front wheel, so you'll basically be in an upright position, as opposed to being flung into a horizontal position if the same occured on an upright.

One of the (many) reasons the handlebar comes exactly across the end of the telescoping front tube is to ensure that should you be flung forward onto it, your weight will be spread across the width of the handle bar, rather than onto an exposed stem as is so often the case on other bikes. (ask me how I know that!)

 

[JimParker]

Hi Brider,

Wow, you have a vivid imagination. John is absolutely correct. There is nothing on the Silvio that would tear open your neck or puncture your sternum in a front end collision. Directly in front of your upper body on the Silvio is a wide tubular handlebar. This is secured by four bolts to a bearing clamp that attaches to the telescopic front tube (TFT). In a front end collision, you may impact the handlebar, but not the TFT. I hope we all can avoid front-end collisions, but I'd much rather be on a Silvio, than a road bike. Better to hit with your feet first than your head. Thanks for the question.

 

[JonB]

johntolhurst wrote: One of the (many) reasons the handlebar comes exactly across the end of the telescoping front tube is to ensure that should you be flung forward onto it, your weight will be spread across the width of the handle bar, rather than onto an exposed stem as is so often the case on other bikes. (ask me how I know that!)

How do you know that?

 

[John Tolhurst]

JonB wrote:

johntolhurst wrote: One of the (many) reasons the handlebar comes exactly across the end of the telescoping front tube is to ensure that should you be flung forward onto it, your weight will be spread across the width of the handle bar, rather than onto an exposed stem as is so often the case on other bikes. (ask me how I know that!)

How do you know that?

The handlebar of the Silvio goes across the end of the front tube because I designed it that way, the Silvio does not have a convensional stem at all.

 

[JonB]

johntolhurst wrote:

JonB wrote: How do you know that?

The handlebar of the Silvio goes across the end of the front tube because I designed it that way, the Silvio does not have a convensional stem at all.

Oh, and here i thought you tried it and escaped unharmed.

 

[Peder Torgersen]

A fellow worker broke his arm recently on a MTB with disk brakes he was drinking water with his right hand so it was not on the handle bar going down a hill and he used the left brake and the front wheel turned and he lost control and fell.
On a Sofrider/Silvio this wouldn’t have happened because you have good control with your feet to help control the steering. I have also mounted a front disk brake on my Sofrider it’s more powerful than the rim brake. Being able to stop in a controlled matter is important on all bikes and recumbents.

Peder

 

[JonB]

Peder Torgersen wrote: A fellow worker broke his arm recently on a MTB with disk brakes he was drinking water with his right hand so it was not on the handle bar going down a hill and he used the left brake and the front wheel turned and he lost control and fell.
On a Sofrider/Silvio this wouldn’t have happened because you have good control with your feet to help control the steering. I have also mounted a front disk brake on my Sofrider it’s more powerful than the rim brake. Being able to stop in a controlled matter is important on all bikes and recumbents.

Peder

You can still flip around with a diskbrake on the front wheel. I know, i almost tried it. Or rather i quickly released the diskbrake once i realized i was only riding on the front wheel meaning the rear wheel slammed into the ground. Luckily the pedestrian had time to jump aside so i didnt hit anything. But... be careful with good front brakes.

 

[Peder Torgersen]

JonB wrote:

Peder Torgersen wrote: A fellow worker broke his arm recently on a MTB with disk brakes he was drinking water with his right hand so it was not on the handle bar going down a hill and he used the left brake and the front wheel turned and he lost control and fell.
On a Sofrider/Silvio this wouldn’t have happened because you have good control with your feet to help control the steering. I have also mounted a front disk brake on my Sofrider it’s more powerful than the rim brake. Being able to stop in a controlled matter is important on all bikes and recumbents.

Peder

You can still flip around with a diskbrake on the front wheel. I know, i almost tried it. Or rather i quickly released the diskbrake once i realized i was only riding on the front wheel meaning the rear wheel slammed into the ground. Luckily the pedestrian had time to jump aside so i didnt hit anything. But... be careful with good front brakes.

The main problem of the accident which involved the MTB was he lost control of the front wheel it turned sideways when he applied the front brake he only had one hand on the handle bar.
I don’t think he applied full power on the brakes.
I agree full power on the front disc brake with a high speed can be dangerous.
Practicing stopping at slow speeds and increasing the speed some can be useful when you have to stop in a critical situation.
You were lucky some situations happen so fast you don’t have much time to think what to do.

Peder

 

[John Tolhurst]

JonB wrote:
Oh, and here i thought you tried it and escaped unharmed.

Sorry Jon, how I know that the stem on a regular bike can hurt is a funny story of a 10 year old boy on his Christmas present new bike, to which his older brother had added a speedometer. Trying to see how fast he could go, said boy hit the rear of a stationary car. From then on, my beautiful new red bike with sturmey archer 3 speed hub had a bent frame near the top of the down tube, which made it handle funny i suppose and it had less trail even with the replaced fork. Nice thing to do to your 1 day old best Christmas present ever! The stem bruised my lower abdomen. The car I hit was one like this:

 

[JonB]

Peder Torgersen wrote: You were lucky some situations happen so fast you don’t have much time to think what to do.

Thats why i try to think in advance, like always having 1 hand on the handlebar, even if it means i can not twitter while riding my lovely Cruzbike

Not that i twitter at all, but hey i could see someone trying to twitter their cruzbike experience using a mobilephone and no hands on the handlebar.

 

[brider]

Thanks to John and Jim for your replies. Unfortunately the wording of my post was misleading. When I wrote "right into,", what I actually meant was "heading directly for." I also appreciate that the Silvio's "stem" does not stick out beyond the handlebars except for the metal that wraps around the bars. However, my original concern still stands to some extent. Getting the handlebars in the chest doesn't sound horrible, but the possibility of the bars striking the neck area is pretty scary.

It's hard to predict what would happen to the body in a head-on crash. Both the arms and legs will tend to buckle, and, if you assume the center of gravity of the bike and rider is above the front axle, which is the point that the impact force would be applied to, then the bike and rider will start to rotate about the front wheel as John pointed out. Would the body tend to head up and over the bars, or would the body tend to slide under as the legs are unable to hold the rider on the seat? I couldn't make a prediction.

I guess the truth is that in a serious front-on crash, even the most perfect of bikes can't prevent injury to the rider. Having said that, I'd still feel safer if the handlebars were lower.

 

[John Tolhurst]

The Silvio handlebar height can be adjusted vertically by adding or removing spacers above the headtube. These are small adjustments. On long armed riders, the bars are pushed further forward and are therefore lower.

 

[brider]

Good points, John. I wonder if anyone has tried a handlebar like the one you supply with the Sofrider on the Sylvio? It would allow the stem to be adjusted even further forward, and would also allow use of the SRAM twist shifters, which at least this writer thinks are perfect for a FWD bike.

 

[John Tolhurst]

brider wrote: Good points, John. I wonder if anyone has tried a handlebar like the one you supply with the Sofrider on the Sylvio? It would allow the stem to be adjusted even further forward, and would also allow use of the SRAM twist shifters, which at least this writer thinks are perfect for a FWD bike.

On the Silvio I connected - with one telecoping tube - the handlebar to the BB. I felt this was very important in making an efficient bike. You may have noted how the down tube on uprights has gradually gotten larger in diameter to better take upper body rotational forces. The silvio front tube performs the same function. Everytime you add a joint (stem or whatever) you compromise the structure a tiny bit and these tiny bits add up. If the efficiency that took Maria Parker 211 miles in 12 hours doesn't float your boat, then the sofrider would be choice. And on the sofrider, the body does indeed shoot clear of the handlebars in an accident (ask me how I know if your must :| ).

 

[brider]

John, thanks again for the reply. I wasn't thinking of adding any additional components, but was wondering about bolting up sofrider-type handlebars right where the normal road bars bolt up. It seems, at least from a distance, that this ought to work, but maybe there are some details that I'm missing, given that I don't have a Silvio in front of me. Of course, if you'd like to ship me a Silvio so I could figure this out myself, I wouldn't mind a bit!

 

[Lief]

I am slightly off topic here but every time I see/hear/read this reference

johntolhurst wrote: ...If the efficiency that took Maria Parker 211 miles in 12 hours doesn't float your boat...

I get unbearable to be around* all over again.
It is just really awesome.

* non-bike riders, wedgie bike riders, bike racers, my wife, my kids...they all say "Yeah you told me that already."