Something new - rather old - or (has Larry gone back to the DARK SIDE)

LarryOz

Cruzeum Curator & Sigma Wrangler
Larry Oz's new ride:
Giant TT rig.jpg
Sweet huh??!! - The guy said it was faster than "anything" he had ridden... Well, he obviously had not ridden my Vendetta.

V20 at BP Park.jpg

No - I have not gone back over to the "dark side", but I do want to get to the bottom of how and why a DF can climb with so much less power and figure out if anything can be discovered that can be used to help the Vendetta climb with less power too.

Testing plans:
Outfit both bikes with the same weight (may have to add some to the Giant)
Use the same rider, cranks, wheelsets, chain, helmet, shoes, etc.

Testing protocol:
  • Coast down testing on a local hill.
  • hill climbing under constant wattage load (different grades, and different wattage levels)
    • - test Giant fully seated for one run, then fully standing for another
    • - test the Vendetta fully laid back in seat, and then leaning up pull on handlebars
  • track loops under constant wattage load.

Any other ideas from the group?
 

Emeljay

WiskersBlowinInTheWind
Max tire pressure vs 15-25% under max. I generally ride about 25% under max to get smoother ride. When riding at full pressure on smooth surfaces I "feel" faster, but at full pressure on bumpy surface don't seem to go as fast and teeth seem to be about to crack and fall out!:confused:
 

RojoRacing

Donut Powered Wise-guy
I think your fully seat or standing or leaning froward ideas are fine to test but flawed for proper comparison test. The leaning forward on the V seems like a huge waste of effort with no real gains, your test and my race results should make that clear. Any good DF rider will cycle between sitting and standing based on a bunch or variables that to left to the riders discretion. Limiting yourself to one or the other is a pour representation of the bikes true potential. Im not sure you as a very dedicated recumbent rider have the feel to bring out a DF true climbing nature. For this test to work you'd need to become more acclimated with DF and climbing like myself.


How long will the test climb be in mins and at what average grade?

I've already stated in the past that I believe the vendetta's handicap on the climbs is 3 fold. I'd build your tests with these three things in mind.

1. It's on average 9 lbs heavier
2. The rider can't switch between standing and sitting to spread the load among other muscle groups. This is mostly a problem on climbs longer then 10 mins that also have much steeper kickers mixed in.
3. On grades over 12% traction starts to become an issues requiring techniques that sacrifice energy for stability.
 

Zzzorse

Zen MBB Master
1. It's on average 9 lbs heavier
2. The rider can't switch between standing and sitting to spread the load among other muscle groups. This is mostly a problem on climbs longer then 10 mins that also have much steeper kickers mixed in.
3. On grades over 12% traction starts to become an issues requiring techniques that sacrifice energy for stability.

Jason, do you think there is anything that can be done about #1 on your list through a design or a materials change? Where is that extra 9 lbs coming from?
 

DavidCH

In thought; expanding the paradigm of traversity
Change the front fork assembly to be a carbon graphene combo. (Even I would buy that)
 

RojoRacing

Donut Powered Wise-guy
Changing the entire bike to carbon and refining the design to match what carbon can dowould probably drop most of that 9lbs. You'll never get into the 15-16 lb range on a vendetta simply because there's more material overall in the design over a bare bones DF bike. The cost of such a change would probably force CruzBike to start charging $8000 for just the frame though.

Almost every accessory we add to these bikes requires some kind of special attachment piece to get it to work with a recumbents which adds the the overal weight of the bike. Water bottle cages are a great example. On a DF bike each cages weights 25-30 grams. On a CruzBike each cage weights the same but now you need a special bracket that'll attach the cages to the headrest and it is 4x as heavy as both cages combined. It's little things like this that slowly add up to that 9lb difference.

Now someone could claim mounting the bottle below the seat doesn't require extra hardware. This is true(kind of) but it's also not most people preferred position for both aero and functionality reasons so I don't consider it as the main mount.

There's just so much market saturation fir the DF bikes that they are constantly refining them to be better. In comparison tiny companies like CruzBike decades behind I the process of refinement. Even with that said the vendetta is still a machine to bring fear to the hearts of any $12,000 carbon DF bike.

A great example of a massive company tossing money to the wind just to play around with a hobby project like DH mtb racing would be when Honda built their factory bikes. Only a couple where ever made and they destroyed the field before disappearing completely. Get a company with that much backing behind a recumbent design and you'll see ultimate speed. http://www.downhill247.com/downhill-posts/inside-info-honda-rn01-the-silver-bullet/
 

ratz

Wielder of the Rubber Mallet
Jason, do you think there is anything that can be done about #1 on your list through a design or a materials change? Where is that extra 9 lbs coming from?

It's in the Boom; the Extra chainstay in the front; and the beefed up fork, and the stock handle bars.

Boom = 2.333 lbs
Fork = 1.75 lbs
Frame = 2.75 lbs
ChainStay = 1 lb
Heatrest pipe = .6lb
Seat = 1 lbs
Handlebars 1lb

Base parts = 10.43 lbs

Measured on my scale this afternoon.

The full build on a V20 is 26lbs and has a roughly a 10lbs disadvantage to the best DF bike. The Bike of the year from 2016 the Trek Madone; in full on race configuration is 15.7lbs and costs $14,500. The V20 is $4500. So that gives you $10k in your pocket to try and close the gap with part selection.

If you want a final setup to be light for a race setup you can shave lbs from on the final build by working the stock parts:

1) Cut down the boom (need calculate the minimum insert for strength given the target length of the boom, no simple math, but not hard),
2) Shorten fork stem; ounces matter
3) cut off the unneeded parts off the headrest pipes
4) Use Carbon handle bars

I think, if you maximize everything you can approach a 2.0-2.5 lbs savings. (Note I'm going to figure it exactly with my current projects)

Then when you pick parts pick the lightest you can afford. Be a weight wennie if you are going to compare to a full on weight wennie bike. Never loose sight of how much those 15lb bikes cost and remember they always lie about the numbers in there favor. aka they don't weight the bike with bar tape; tool bags, water bottle, etc on them. How heavy is your bell and mirrors?

So

1) Use carbon bottle cages
2) Use the lightest components out; that includes things like $250 cassettes.
3) Use the lightest Aero wheels you can find

All said on done you'll be out about $9.5k and you will be down to about 20-21lbs. You'll will still be 5 lbs heavier but you'll have 4-5k in you pocket. So then lose five lbs of body weight and call it good. Jason sorry man your so skinny you just have to train harder.

Just my tips on making the bike light as it stands......




Now since this will then of course lead to chants of "use carbon" lets look at that.

Carbon is going to be 64% the weight of 7005 alloy.... so the simple thought line goes that you have 9.33 lbs in aluminum in the bike. so you should be able hit 6.5 lbs with the frame instead of 10.43 for a total of about 21 lbs on a stock $4.5k build... that would be in a perfect 1 to 1 swap which never happens.

You use carbon differently and the lines change. Carbon leads to curves; alloy leads to pipes and triangles (hydro forming not with-standing). So your not going to get the weight down with a materials change accept to maybe titanium; without some serious redesign, and costs. While I'd sign up for a limited edition Titanium V20 I am not holding my breath... (but keep me on the list)

So back to carbon, the Yellow Vendetta was designed to test the constraints of moving toward carbon in the future hence the huge diameter boom with thin walls and a welded in cut out for the fork stem bracket. Aluminum does not call for that sort of design but, carbon does; as do the hydro formed frame shapes. John T was very open about that back in the day. He was thinking about it as a future iteration.

In the end it is easy to summarize that it apparently did not turn out to look cost effective to go the carbon path. The current designs have instead swung to a focus on equal or better performance and sustainability and viability; and bike sales.

This is total opinion but if you wanted a Carbon V20-C model the following evolution would be necessary and it's going to be expensive:

(1) Develop a carbon back half of the bike; probably in two lengths for different heights (use current front) This gets you a more expensive bike, that is possibly more comfortable on the road but, is barely lighter or maybe heavier. The Hydro-formed 7005 frame section is super light now. At this stage you'd have a higher price but, no noticeable gain. That's not a good business choice. You do this first because "front wheel" aka our back wheels; have a stable non-changing design.

(2) Then follow up with a carbon boom, which would probably look like the old yellow boom to be strong enough; that is an arguable positive gain but, an expensive one. The bike as a result is going to get more fragile. Sliders are notoriously difficult to do in carbon. It hass gotten better in the last few years; CA2 and Encores don't need the giangantic clamp brackets of years gone by on their carbon sliders.

(3) Finally try and develop a carbon fork that can handle the MBB stresses. (Ever look at a home builder threads; they always using exisitng carbon forks because it's darn hard to make a solid carbon fork. Again supper expensive because you are the only one that needs a fork with a 132mm drop out. Lots of setup cost; and finally some gains in total weight reduction. The Problem here is drive wheels are in a heavy state of flux with the move from 130-->135 --> 132 and now 142-145mm through-axle. Getting trapped and having to redesign your carbon forks to keep pace with the bigger industry could be a mess.

If you took it all the way, In the end you are going to have a $6000-80000 framekit before you put parts on it (assume a near zero profit bike for Cruzbike while they pay off the molds). All that to save maybe 4-lbs. Why only 4 lbs, well there is still going to be a lot of metal formed into that carbon; no way the Bottom Bracket is going to be press-fit inside a carbon shell; it is going to have to stay metal wrapped in carbon for the MMB forces to to be handled safety....

End of the day, it is important to remember these are mainstream bikes meant to fit many and varied riders; these are not Zockra one offs at twice the price. (see how well that worked for them?)

Lastly for what it's worth a lot of the potential market for the V20 already complain it's too expensive at 4.5k; the market isn't looking for a V20-C at $9k.... they just aren't. Also ever compare how well a used V20 sells compared to a used Zockra?

Any doubt about why carbon forks are not easy here's you photo proof...

39889_1497258024998_2985982_n.jpg 39698_1497258145001_6809636_n.jpg 39228_1497257864994_4707563_n.jpg
 
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Zzzorse

Zen MBB Master
Do you racers need an adjustable boom, could it be lightened further by a fixed length unit sized to your specifications once you know them?
 

RojoRacing

Donut Powered Wise-guy
That's like asking if a DF rider needs an adjustable seat post. In fact my Ridley Noah does not have normal sliding seat post. I was required to measure and then cut it to length which if done wrong makes the whole frame worthless. I am able to add back in up to 15mm of height with shims but that not a ton of adjustment. The only reason this works is because DF designs are so standardized that a bit fit is generally spot on from the first ride if done correctly. Also the frame coming in 5 different sizes does hurt as well. All of this is impossible at anywhere near the price point that people are willing to pay.

@ratz I think we've hijacked Larry's post enough and maybe these last few responses should go into their own thread.
 
hill climbing under constant wattage load (different grades, and different wattage levels)
  • - test Giant fully seated for one run, then fully standing for another
  • - test the Vendetta fully laid back in seat, and then leaning up pull on handlebars
I don't think changing positions (while maintaining a fixed load) would change climbing speed. Calories burned and muscle variation would change and that can impact the outcome of a race.

I only sit up to improve low-speed stability, doing so burns energy from arm & back muscles and pushes up my diaphragm. I'll add arm input and sometimes lift my hips off the seat to help increase power output and recruit different muscles. Didn't Jim have a video about climbing with a 'bent?
 

ratz

Wielder of the Rubber Mallet
Do you racers need an adjustable boom, could it be lightened further by a fixed length unit sized to your specifications once you know them?

Some adjustment is needed for crank changes; shoe and pedal changes, but not a lot.

What would be great is if @mzweili could use his mad engineer math skills to tell use how much of the an over lap we need on the boom/slider; to maintain the same rigidity as a solid piece of aluminum. There really is A LOT of over lap on the boom; and If you are pretty sure you aren't going to resell then shorting that makes sense.

Boom outside diameter = 41 mm
Boom wall thickness = 2.5 mm

Slider inside diameter = 41.1 mm
Slider wall thickness = 1.5 mm
 

trplay

Zen MBB Master
I've seen somewhere 2.5 inches past the slot but can't remember where. My guess is an 8-12 inch boom allows for a little adjustment and a nice chunk of weight reuction.
 

RojoRacing

Donut Powered Wise-guy
Some adjustment is needed for crank changes; shoe and pedal changes, but not a lot.

What would be great is if @mzweili could use his mad engineer math skills to tell use how much of the an over lap we need on the boom/slider; to maintain the same rigidity as a solid piece of aluminum. There really is A LOT of over lap on the boom; and If you are pretty sure you aren't going to resell then shorting that makes sense.

Boom outside diameter = 41 mm
Boom wall thickness = 2.5 mm

Slider inside diameter = 41.1 mm
Slider wall thickness = 1.5 mm

I find the whole front end of the Vendetta to be rather flexible under high efforts compared to my aero road bike which is on the rather stiff side of the DF would. We have to be loosing a constant % of efficient under lower cadence high load climbs and sprints. Where I notice the flex the most is on the trainer where I don't have anything else to really distract me.
 

mzweili

Guru
Round tubes are ideal for the boom/slider assembly. I wouldn't try to calculate something because of the rather complicated force-vectors.
I guesstimate that the boom could have a thinner wall.
Shorten the boom is much easier, and some destructive load testing would be the method to find the limit.
 

super slim

Zen MBB Master
Titanium is the way to go, with thinner wall sections for the existing frame and front triangle ODs, BUT expensive and HARD to weld!
Most of my DF riding friends have gone from Al, to CF, and now VERY Happy on Titanium!

Stay away from Carbon, as too many failures, even with top frame builders! Look at Ratz's front forks!

The minimum engagement on an aluminium 27.2 mm dia Cane Creek suspension seat post is 98 mm, so 3.6 times the diameter.
Can someone with another Al seat post check what its Minimum engagement is?
Can someone with a CF seat post check what its Minimum engagement is?

If the 3.6 X ratio is correct then 41*3.6 = 147, approx 150 mm minimum engagement of the Slider tube is required!

With two clamps on the headrest tubes, these only need to just extend past the 2nd clamp!
I was surprised that I must have a short body trunk, as the headrest tubes are finally in their shortest position!
The distance when sitting from a seat, to the top of my shoulders (is this a special Y?? seam) is only 26.8"
What are other riders Y?? seam?
 
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