getting boom length fit correct

[hamishbarker]

When my short legged brother in law visited, i changed my vendetta 1.5's boom length but marked the old position.

When i refitted it back afterwards, i checked the heel to pedal fit and found my existing position was much longer than it would be for my heel toreach the pedal with a straight leg.

So i started adjusting...and adjusting! Ifinally got the length set so that my heel reaches the pedal, i was set about 40 to 50mm longer before, couldn't believe it. I've been riding it that way for months. I did notice a little ache in my arches or maybe calf muscles at first, but it soon went away so i guess i got conditioned to the position.

I guess on a df bike, that amount of adjustment would be painful on the saddle, but on the vendetta i guess i was just pointing my toes to make up the extra length!

I wonder if this was detrimental with regard to muscle utilization.

Any thoughts or comments from others on how their fit went, or has perhaps changed over time?

 

[MrSteve]

Totally understand!
Yes I do.
I started off on the Sofrider with the boom pretty short and, over time, extended the boom.
I rode it with the boom over extended a bit and my knees told me to shorten it, where it's been for years now.
Literally, years.

On the v 1.5, I adjusted the boom to match my Sofrider.
They're so close ergonomically, the modified S. and the V.
But, they're not, as it turns out: the V's seat back is different which affects everything else.
A few weeks later, shorter crankset installed, stem extender installed and now?
I'm thinking I'm happy....
My heels are kissing the pedals the way they should.

If the seat gets modified, then the boom will be readjusted.
But not yet.

 

[jond]

When my short legged brother in law visited, i changed my vendetta 1.5's boom length but marked the old position.

When i refitted it back afterwards, i checked the heel to pedal fit and found my existing position was much longer than it would be for my heel toreach the pedal with a straight leg.

So i started adjusting...and adjusting! Ifinally got the length set so that my heel reaches the pedal, i was set about 40 to 50mm longer before, couldn't believe it. I've been riding it that way for months. I did notice a little ache in my arches or maybe calf muscles at first, but it soon went away so i guess i got conditioned to the position.

I guess on a df bike, that amount of adjustment would be painful on the saddle, but on the vendetta i guess i was just pointing my toes to make up the extra length!

I wonder if this was detrimental with regard to muscle utilization.

Any thoughts or comments from others on how their fit went, or has perhaps changed over time?

hamish i started with the heel on the pedal method. once i learnt the basics i started pushing out the boom in a bid to make my knees happy in 1 cm increments. eventually i needed to pull it back in a bit.it now sits about 50mm from my start point. here i found the sweet spot for me. maybe you had it right in the first place. feel and comfort. and in my case i can generate power easier too in this extended position. i think there is some natural adjustment room at any rate by moving up down the seat. my legs definitely feel more comfortable extending more on the V than compared to my DF. my trikes have approx the same extension.

 

[hamishbarker]

Jon, interestingto hear your similar experience. The final adjustment i did last night is too short i think, so maybe i'll back it out 5 or 10 mm tonight.

With the boom too long, i wonder if utilization of the muscles which can do work as the ankle flexes would be reduced. a question for the next turbo trainer session...

 

[bladderhead]

Easy to get the saddle height right on a wedgie. A 'bent is more interesting. Different seat design or height make a difference. No formula. I just keep adjusting it. My legs extend slightly more on the Silvio than on the Grasshopper. Both bikes seem right to me.

 

[MrSteve]

hamish i started with the heel on the pedal method. once i learnt the basics i started pushing out the boom in a bid to make my knees happy in 1 cm increments. eventually i needed to pull it back in a bit.it now sits about 50mm from my start point. here i found the sweet spot for me. maybe you had it right in the first place. feel and comfort. and in my case i can generate power easier too in this extended position. i think there is some natural adjustment room at any rate by moving up down the seat. my legs definitely feel more comfortable extending more on the V than compared to my DF. my trikes have approx the same extension.

Yes!
A reclined seat certainly does open up your adjustment choice on the fly, while you're riding.

My Sofrider has two custom seats: One is reclined at 30 degrees and one is reclined at 18 degrees.
The 18 degree seat, the final configuration, has the seat pan an inch lower and about an inch farther forward than the 30 degree seat's seat pan.
The boom doesn't need adjusting when the seats are changed.
Also, when going for top speed, I can scoot forward another inch or so and get a little bit more reclined/aerodynamic on the 18 degree seat.
This scooting forwards and back, while riding, works fine on the V... just like Jond found.

 

[LarryOz]

I think we are all built a little different and the comfort/fit/feel equation will always probably be a variable somewhat.
For me, I find the best feel is to have my toes pointed almost straight up when fully extended, but even more-so (jumping on my crank-length soapbox now), it is crucial to me to make sure my knee angle is not much beyond 90 degrees on the back slope.
I have notice 2 specific things:
#1 - With my toes pointed straight up on full extension, I find it much easier to pull down and back through the rotation. If my toes are more pointed it is harder to do with much power.
#2 - If on the back-stroke my knee is really bent way past 90 degrees, my knee hurts. Plus, if the angle is around 90 it is much easier for me to apply full power earlier on the forward stroke once I have gotten the pedal past the "closest" point to my body.
That is my 2 cents worth - that's what works for me.
Good Luck.

p.s. On other thing that makes all this experimentation with the boom length easier is have the Di2 system - so you can move you boom in and out without having to mess with the FD! So nice.

 

[fred_primus]

Sram is coming out with a fully wireless system.

 

[ratz]

#1 - With my toes pointed straight up on full extension, I find it much easier to pull down and back through the rotation. If my toes are more pointed it is harder to do with much power.

Hmmmm... I never considered pulling down. Crap I think I'm going to have to cut silver slider a little to get boom short enough to try that and that's at least a full days project maybe two. Larry you might have finally enlighten us to the crazy power you generate. I wonder if any one else is pulling down on the end of the power stroke. Might just have to test on the silvio instead hmm hmm hmm...

 

[bladderhead]

I still think it was a good idea to cut the boom of my Silvio. I believe Bruce B thinks it was a good idea to cut the boom of his Vendetta. I still think it is a good idea to push down with my heels.

I think it is a good idea to attempt to catch Larry. Do not attempt to use his slipstream, because if you are that close, you will run him over when he falls off.

 

[Eric Winn]

I wonder if any one else is pulling down on the end of the power stroke

Yup

 

[Martinius Berg]

Recumbents give some unexpected challenges . Things where way easier when we where kids in the 70-tees. People with upright bikes and with shorter legs mounted wooden blocks on there pedals to compensate. When following the factory instructions for the boom offset your good to go .................... wroommmmm.

Have a nice weekend ladies and gentleman

 

[DavidCH]

and that's at least a full days project maybe two

I will second that. I think this would be most useful. Larry might have let the cat out of the bag with that one.