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dgtaylor
11-04-2009, 08:33 PM
I was looking at the warrior plans and it talks about increasing the ground clearance to prevent heel scrub. I wear size 14 shoes, so I was thinking about raising the clearance 1.5 to 2 inches.

If I lengthen the dropouts and the axle mounting tabs 2 inches, then raise the booms and seat tube clearance 2 inches when I set it up to mark the tubes, would that leave most of the other angles and lengths the same?

I think that would work, but just want to make sure I haven't missed anything.

Thanks

Odd Man Out
11-04-2009, 09:34 PM
Why don't you just simplify things and raise the front boom (the last section where the bottom bracket is located) a bit instead???

dgtaylor
11-04-2009, 10:08 PM
I didn't know if it would make it feel like I was riding with my feet above my head. I haven't had the chance to ride a recumbent and I am not sure if I would like my feet raised so high. I was thinking that the design probably had the right relationship between seat height and the bottom bracket and was just trying to figure a way to keep that relationship.

If anyone has ridden a bike with the bottom bracket raised in relationship to the bottom of the seat I would love to hear how it felt.

One more thing, although the bike looks fast, I am more interested in distance rides where I am comfortable rather than top speed if this makes a difference.

imamedik
11-05-2009, 12:11 AM
In conjunction to what OMO recommended with the boom you could also use a scrap piece of the 1.5" tubing for a seat mount, that way you should be able to keep the seat height and bottom bracket relationship.

jimFPU
11-05-2009, 08:30 AM
I haven't had the chance to ride a recumbent and I am not sure if I would like my feet raised so high...

If anyone has ridden a bike with the bottom bracket raised in relationship to the bottom of the seat I would love to hear how it felt.

Find a local Bent riders group near you and give them a call. Someone (most anyone) in a local group will give you a few test rides, and some will even let you use a 'spare' bent. The guys in the DFW area do it all the time to encourage more people to get bent!

Freth
11-05-2009, 09:41 AM
Just angle the front section of the main tube upward ... It's your feet not your rear-end that you want higher clearance on. When you've got it set up on those little buckets out front ... put a 2x4 block under the front piece to either raise the whole thing higher or just angle the front end upward. (look at all the other tadpole trikes on the market ...) :-)

TheKid
11-05-2009, 01:29 PM
I'm one of those who need the BB below the seat, in addition to shorter cranks. I discovered this after building and rebuilding a couple of bikes. You could get a general idea of how high you could stand the BB above the seat by placing a chair against a wall and "air pedal" at various heights. From what I've read, some riders only needed shorter cranks to avoid knee and hip pain with higher cranks, others could not tolerate cranks higher than the seat at all.
I'd say you're on the right track of raising the seat level in relation to how much you need to raise the BB for ground clearance of your feet. All you'd have to do is weld the rear end 1 1/2-2" lower on the seat tube, or make the seat tube 1 1/2-2" shorter. Then before welding the crossmembers to the boom, put the boom at the height you need it using buckets or whatever to prop it up, and check the angles. You'll probably have to reduce the upward angle a few degrees.

kevinp
11-05-2009, 01:56 PM
After reading this thread I checked the clearance on mine, its going to be a bit tight maybe an inch - inch and a half clearance. While looking at the boom I did consider cutting and angling the boom up but ... then I thought why not just make the brkts on the BB longer and weld a piece of box under the BB to raise it up a bit you would only need an extra 1/2 inch I suspect.

I would change the cranks but I have none that are suitable at the moment.

dgtaylor
11-05-2009, 11:05 PM
OK, it looks like the easiest way would be to combine OMO's and imamedik's ideas to raise the seat and bottom bracket.

But since I am waiting on my tubing to arrive and I'm still practicing my welding (it's been 30 years since I welded anything) I have had time to keep studying the plans. I think I have another idea.

To those who don't have the plans I apologize, but the best way I know to describe what I am thinking is to reference image numbers in the plans.

I am raising the ground clearance 2" in this example. I might not need that much, but will go ahead and use it just for this example.

Considering diagram 2 on page 32. If I lengthen the dropouts 2 inches then increase each measurement to the ground 2 inches, all lengths of tubing and angles should stay the same. Now you continue with the build as per the plans.

When you get to the steering boom tubes. If you connect them to the head tubes at the 90 degree angles, when you connect them to the frame, the wheels will lean outward since the frame is now taller. If I am looking at this right, you need to connect the steering boom tubes to the head tubes at an angle with the boom tubes angled up from the head tubes. You will need to figure the angle by setting the frame at the correct height and comparing it to the wheels with the head tubes attached.

If my thinking is correct the ground clearance can be changed by simply making the dropouts longer and changing the angle the steering booms attach to the head tubes. All other angles and measurements will remain the same so all dimensional relationships will remain the same. This is a whole lot better than my first idea. Does this make sense?

To be honest, when my tubing arrives I will probably go with OMO and imamedik's suggestion. But it is fun trying to figure out if there is another way which will keep everything looking and feeling close to what the designer intended.

ken will
11-06-2009, 07:20 AM
One of the best things about building it yourself is if you take it for a test ride and decide something would be better if it was different, you just take out a hacksaw or angle grinder and change it.