rf10

Hi,
I wrote here in August about the bad accident I had on my Longbikes Gulfstream tandem, when I broke my leg badly. My wife says I should just ride the tandem with her, not alone, as I was doing when I fell - she can cushion the fall. So now I feel that the problem really is the small front wheel of many recumbents. I'm looking for a LWB USS bike with two large wheels. Is there such a thing?
Thanks,
Dick

Jeff Wills

Not in regular production, AFAIK. The problem with a LWB-style tandem is that the wheelbase starts getting huge. Adding a large front wheel to that will just grow the wheelbase even more.

I'm interested: why do you think the small front wheel caused your accident? In my years of recumbent riding (and a couple falls) it's never been a factor, IMO.

If you're interested, you should get in touch with Gary Hale. He's built large-wheel LWB bikes for a while, and he's gone one better than your tandem:

VegasTriker

I used to ride a long wheelbase 1997 Linear, my first decent recumbent. When I bought it, I was a real newby and didn't take into account the frame length since the parts on the bike could be moved all along the frame to accommodate any sized rider. The front end (20" wheel) was very lightly loaded compared to the weight on the rear wheel, making it easy to cause the front end to slide out on a sharp curve or wet surface. This was before the local water district imposed strict conservation rules about irrigation water running off people's property and many intersections were often wet from runoff. It was pretty easy to lose control while making a turn if I took it too fast or too sharply on the wet surface. Maybe this is the problem with your tandem - too lightly loaded a front end making losing control more likely. I rode that Linear over 5K miles but soon became accustomed to being cautious making turns if the road was at all wet.

purplepeople

I agree with Jeff that the small wheel was likely not your problem but disagree with Vegas about weighting on the front wheel. My best guess is that riding the tandem solo put too little weight on the rear wheel and your crash was from losing rear traction. The resulting low side dropped the full weight of the bike on your leg.

But, if you believe a larger front wheel will help, go for it.

:)ensen.

rf10

Thanks for these responses. The accident happened on starting up from stopped at an intersection, steep downhill, sharp left turn, pavement with bad washboard, possible flat front tire. Started up and in one second I was on the ground with both bones of my left shin broken by the main frame bar. Any insight on why that happened is most welcome.
We've taken that bike to France twice - Alsace (actually a Ryan bike) and Dordogne. Even loaded with camping gear we never had a bad fall, though it was not very stable at low speed. I did need to be careful on turns.
It just seems to me that quite obviously a small front wheel is less stable than a large one, at low and high speed. Don't you agree?
I'm now looking for a single, not another tandem, as I still like that one for both of us. Ideally LWB, USS, large front wheel. I haven't seen anything except the Flavobike, which is a little scary.
Thanks,
Dick

BlazingPedals

I'll tone down the quote, so make this a paraphrase instead of a quote, but "anyone who uses the word 'obviously,' obviously doesn't know what they're talking about." The size of the wheel isn't as important as the loading and the geometry. If anything, a LWB with a full-sized front wheel will be loaded even more lightly in front than one with a 20" wheel. You're looking to replace your LWB with another LWB that will probably have the same problem. If you have your heart set on doing it, at least get one that's larger on you; that way your weight distribution will be a *little* more toward the front.

Jeff Wills

No. Stability has much more to do frame & fork geometry, weight distribution, and control authority.

Remember that balancing is achieved by steering the front wheel under the center of gravity of the bike. The problem with riding that very-long-wheelbase bike at slow speeds is that the front wheel needs to be turned at a much sharper angle to achieve the same balancing force than a similar, shorter wheelbase bike. In your case, you probably lost traction on the front wheel just as you were attempting a radical balancing manuver. Slow speed, a downhill turn and poor pavement probably contributed, but I doubt a larger wheel would have helped.

Have you tried a Screamer? Or is there some reason you're stuck on USS?

FWIW: the guru of bicycle stability, Prof. Bill Patterson, wrote the textbook on the subject: https://www.calpoly.edu/~WPATTERS/lords.html . This information helped in the design of the radically short BikeE tandem, as well as Gary Dinsmore's "Path": https://www.calpoly.edu/~WPATTERS/lords.html

FWIW2: I used to ride a Lightning P-38 recumbent. Despite its short wheelbase, small front wheel, and "twitchy" reputation, I had no problem riding it on all surfaces at all speeds from 0 to 55mph+.

purplepeople

Possible flat on washboard, at speed followed by a sharp left.... and you're blaming the bike?

If the bike itself is unsure of itself even when loaded, I'd say you don't have enough air in the tire, or you've got a problem with the frame (or fork). If you're using a cheap tire that can only be pumped to 60 psi, that could be the cause of your flat as well as the sketchy handling.

As a builder, if I really wanted to try a large front wheel, I'd see if a larger fork and wheel can be fitted and do some test rides. Even though it changes the geometry, you may find it more to your liking.

:)ensen.

PaPa

Not by a long shot;

The authority on HPV design and dynamics (both single and multi-track) was Archibald Sharp - Over 500 pages worth, written over a 100 years ago.

Jeff Wills

What's he have to say about small wheels? :-)

PaPa

In reference to the OP's complaint?... or in general?

IMO, the OP hasn't supplied sufficient detail to accurately lay blame. There is a 50/50 chance the small front wheel may have contributed to his unfortunate mishap, and an equally 50/50 chance that a larger diameter front wheel could have prevented it - but who knows?. However, pilot error has proven in the past to be responsible for many (perhaps even the majority) similarly described incidents - a huge portion of which have large diameter wheels. Maybe the OP should consider 3 wheels instead of 2.

Jeff Wills

Ah, so. I agree with your assessment.

iconoclast

Last year I posted on this forum about how increasing the front wheel size on my EZ Sport dramatically changed the high speed and cornering stability for the better.
I was immediately criticized by most everyone.
Well, a year later I'm still riding with my larger front wheel and I love it.
I kept the small front wheel and fork in case I ever wanted to change back.
However, whenever I carve out a nice turn and feel the stability, I know I will keep the larger front wheel.
Theories are okay, but real world experience really tells the story.
For me, there is no question that larger front wheels are more stable.

purplepeople

Was the improvement from the change in the diameter of the front wheel or the geometry change of the head angle and/or the trail?

:)ensen.

PaPa

https://www.bikeforums.net/showthread...t=#post8454693

PaPa

Quite right, iconoclast.

But yet you persistently believe that your single, $67.93 'conversion' trumps 20 years of LWB experience that includes well over 3 dozen frame up builds from a pile of raw tubing.

gbenth

Here are 2 companies that make bents with same size 26 inch wheels if you think that might help.
https://www.ransbikes.com/Seavo.htm
https://www.lightfootcycles.com/ranger.htm

I really don't believe that a small front wheel caused your fall. I tried to ride a Longbikes Jetstream by myself and felt that I needed at least a 50 lb. bag of potatoes strapped to the rear seat because the rear wheel wanted to lift from the ground. Even worst if I put on the front breaks. Lack of weight on the rear wheel would cause loss of traction and breaking in the rear and make the bike ride like a unicycle with no power to the only wheel that had traction.

iconoclast

PaPa,
Your persistent personal attacks give me a chuckle.
Thanks. I needed a good laugh this morning.
Happy riding.

leverleg

I bet you need look no further for the cause -- the bike's washout was a simple matter of a flat front tire. Over 250,000 miles of riding leads me to the fearful understanding that an almost flat-or-flat one will dump the bike instantaneously in a turn. The bead jumps and exposes raw rim that skates on pavement. Your report back in 9/09 said the tire was found flat. BTW, what's the condition of your laig now, six months later?

BlazingPedals

Nevertheless, he has a point. By changing your front wheel from a 20" to a 26", you slackened the head tube angle and increased the trail; both of which can be expected to have significant effects on handling. You insist that the size of the tire is responsible for 'improved' handling; a few of us are merely saying that the change in geometry is what is responsible; the larger tire was merely a means to an end.

rf10

Well, that's probably true. Did I mention that I have tubeless tires? They're the favorite of my local shop, who has helped me out a lot. I guess it was just a coincidence of a lot of things - the slow speed, sharp turn, steep road, washboard, probable flat tire (though I don't think it could have been flat for long, as I'd just ridden down the 200 yard steep road with no problem).
I live a mile and half from work, a 450 elevation rise. I was riding home that day. I am now, since Thanksgiving, able again to walk that up and down every day, so my leg is pretty good. Still has the 14" stainless pin in it. BTW, it doesn't set off the airline security alarm. The leg still aches and swells some, but doesn't really hurt - haven't taken pain killers since month 3, now month 8. But I don't recommend the experience.
I'm looking for a single recumbent. After all the discussion I'm not sure about the large front wheel, though I agree with the poster who said he felt more steady with a larger wheel. But the geometry stuff plays too of course. Thanks to all for the advice.
Dick

TXiceman

I have been riding a Cycle Genius Raven 700 with dual 700 x 23 wheels for about a year now. Been riding Bents for about 10 years now. Currentl riding a Greenspeed GT5 trike and have the Raven up for sale.

I like the dual 700 set up as it is comfortable and fast. It is very stable at speeds but with the long trail on the front wheel, it is a bit unstable at low speeds. So if you slow down for a lot fro a climb, it can get a bit wobbly, but nothing that was a real problem.

I have ridden the bents with small front wheels and crank forward and I prefer the LWB wit the big wheels on both ends. It is a lot of what you are used to,s o you can't immediately start bad-mouthing LWBs and big wheels.

Ken

gcottay

You and your wife might want to make a trip to the Bicycle Man in Alfred Station or some other quality recumbent shop. It would not only be much more fun than a broken but provide an opportunity to decide for yourself what bike (or trike for that matter) is best for you.

The most stable and best handling bike I've ever encountered is a __________.

Roll-Monroe-Co

Turner makes a USS LWB. I've always found it intriguing to look at. Probably a nice ride. But I also look at that bike and imagine tumping over to the side and breaking my arm because I couldn't get a foot down in time.

https://www.turnerrecumbents.com/products.htm