Bullhorn and Dropbar Options

[Eric Winn]

So does the boom and slider

So does the boom and slider (reversed on Vendetta) overlap at the headset region on the Silvo? Looks like the overlap is much further down from the photos I've seen.

I need to look at a new Silvio in person... Should be hooking up with Tim when it gets warmer. Didn't have time to swing by the Parker's on the way home from Sebring else I'd have scoped one out there. Of course the other danger related to that is I probably would have brought one home with me.

-Eric

 

[ratz]

All the way to the water bottle bolts

Yes the overlap is a lot all the way to the water bottle cage bolts. That is why us short folks have to cut our booms. Mine and the wife's both got 4 in cut off.

 

[ratz]

Mr. GoodBar

Ok progress has been made. This has turned into a long running project, but now I'm getting results that I wouldn't have been able to guess at without doing it. Hopefully this hasn't bored anyone to death yet.

I the bars that I expected to meet my goals have arrived; These Deda LowRiders do indeed work; and the offer up 3 distinct configurations that would work for me. I've got some preliminary photos of the results. So here goes.

Here's the Granny Gear Position thanks to the Shifter Modification from the last Post.

Here's the Cruising Gear position; big ring in front; 3 or 4 from the bottom in back

On the bike at a shallow angle.

On the bike at a steep angle

Ok so as you can probably tell this layout requires an external cable run for the brake until it reaches the entry hole.

However the hand and grab positions work out such that you aren't really grabbing the cable area. Once I cable it and tap it; I'll get some hand close-ups that show where the natural hold points are.

Now I said there are 3 configuration that will work.

Configuration #1 is what you see here; Configuration #2 is to have the bar end brakes installed; and to put the shifters on Paul's thumbies down by the stem clamps, this will require 31.8mm thumbies. That position for thumbies isn't bad at all; as there are 3 distinct hand positions with these bars. One would put the and hands in the aero position out at the end; one is at the curve; and one is in tight. All three are pretty comfortable and strong positions. I was going for 2 positions, I'll take 3 and smile. Because of those multiple positions, I don't have a big issue with the shifters being at the clamp; and it might be better for starting out at intersections where the most rapid shifting tends to occur.

Configuration #3 is interesting; with these bars you could cut off the end right at the bend. If you do that and put a brifter on it. You get basically the same bullhorn back (may be a little longer) and it seems very grippable. I did get these bars in two different widths; So one pair will be sacrificed for the brifter test.

Lastly I did put the R2C shifters on here to see if they work; but they look dumb; but they showed me that this configuration would work with both the brake and shifter externally routed; which would mean someone could avoid the shifter surgery.

The brakes in the photos are TRP RL950 carbon; very nice feel, and I also tested the more common Tektro RL720 aluminum ones those work equally well but have a definite left and right lever.

Right now I'm sure I will do full wired testing of Config 1. I'm going to mock up Config 3 and that will tell me if I should wire it up and test. I'm undecided about configuration 2. I'll probably mock that one up and get a feel for it; But I'll probably only pursue that one if I'm wrong about the cables not being an issue with config 1.

The next big question is whether John thinks it would be safe put an exit whole in the under side of the Silvio boom so that the cables could be run internally the whole way like the Vendetta. Would have to drill throw two tubes; and position of boom would have to be fixed. Neither is a problem assuming the thickness of the boom is enough not to compromise it's strength. Obviously I'll be responsible for my own demise if I do that; and something bad happens. I'm leaning that way at the moment.

 

[Eric Winn]

BTW, this last configuration

BTW, this last configuration of yours is looking very similar to the custom bullhorns Mr V built.

-Eric

 

[ratz]

Bully for bars

Ok so the handle bar saga is wrapping up; because the bars are on the bike; wired in and tape wrapped.

I mentioned that there are at least two configurations that work. Before I show the final configuration; I have a few shots of the alternative / backup plan that somebody might be interested in. This is my fallback plan.

Advantages of this configuration are:

1) No cable under the tap at the end of the Bars
2) Shifters access bile from two hand positions.
3) No Shifter surgery needed if you are willing to simply swap the left and right sides so that the rear control is on the left and the front is on the right.
4) Front break cable exit below the bar and all cable routing is normal Silvio routing along the outside of the boom

The bars in the photo are 440mm and 460mm are available. There is no leg interference with the shifters for me because the legs don't get back far enough to touch the bar nor the shifters.

The hand grip with the Aero breaks is about perfect; Light breaking; single finger pull and a no cable interference feel.

I have very small hands and the reach for the sifter is very comfortable don't require wrist bend; and the end of the horn provides as excellent leverage point to ensure you have enough strength to shift without engaging the wrist. This picture above really doesn't do it justice.

 

[ak-tux]

Great Bikes Ratz!

Great Bikes Ratz! You have one happy family there!

Just curious, does drilling the boom weaken it?

 

[Ivan]

Full marks to Ratz for his

Full marks to Ratz for his incredible patience (or should I say his wife's patience?) on the handlebar project! Silvio and Vendetta owners certainly have options to choose from. After a couple of months commuting and a couple of centuries on my handlebars, I have not changed their position from what I had in the above. I am happy with them and can split lanes in between cars at traffic lights easily now. I still recommend that new Silvio/MBB riders use the provided flared drops first as they are easier to learn on.

I find that I am more and more holding the bars in the position in the pic below. At first glance, this looks similar to Mrs Ratz's position on the trainer but it is not. While she is pulling back on the bars underneath the brifter, I am pulling back on the brifter just above the brake lever. This is possible because my brifters are angled lower. While Mrs Ratz is holding the brifters similar to how a roadie would hold them "on the hoods" mine is different -- the picture describes it better than I can in words. Sometimes my palms are on the side like in this pic, while other times my palms are more on top of the brifter/handlebar.

 

[ratz]

Elective Surgery - is a success.

Ok so the bullhorn for Silvio 2 journey for me comes to and end here. The configuration is done and it works splendidly so far on the trainer.

Advantages to this configuration:

1) Follows in the footpath of the Cruzbike Bullhorns
2) Compensates for the higher boom angle on the Silvio
?3) Internal cable routing (as much as possible)
4) Finger tip controls in the areo position


Step (1) Modify the SRAM shifters following the Cruzbike lead as documented above.
Step (2) Modify the handle bars as follows:

These are Deda Crono Low Riders at 440mm wide. (420mm and 460mm are available). These are mostly only available in the UK. If you order them from there; expect about a 4 week delivery time. Universal Cycles in the U.S. does stock them, but not the 460mm version. They are inexpensive and really nicely made. The could use about 1-2cm more forward reach for a stock Silvio, but more on that in a bit.

The configuration is the one I showed previously

The first step for this; is to route the cables internal to the bars. That required drilling a hole into the stem clamp of the bars for the cables to exit. Two quick shots side by side with a power drill and then some patience with a good quality file; level me a nice clean opening with out any metal burs. (The Silvo touch-up paint is a match for the bars for scratch clean up. The Shifter wire runs through the bar and the cables for the brakes run through the holes that come fabricated into the bars. You can see here that I have traditional housing for inside the booms; and jagwire metal compression-less housing for the outside routings. In the following picture I have all the housing and CABLES installed with far more cable that I need. That made assembly easier; as I only had to fight with the bars and not the entire bike.

Next since the Silvio boom doesn't have an exit port like the Vendetta, I had to violate my boom. The tap in the picture is where my pivot clamp goes. My front boom has been shorted 4 inches so it does not come past the pivot clamp area. You can see the final opening in this picture. To make it I drilled 3 holes side by side and again worked the file; and then painted it. It doesn't look that pretty here but it's nice and smooth.

For ease of assemble I removed the boom from bike and assembled all the wiring off the bike. The opening show here is sufficient for two cables to exit in the middle of the length; and the other two to exit at the forward end of the hole.

With all the cable prepped I put the pivot clamp back into position; and then used temporary electrical tape to hold the four wires in perfect position to go through the pivot clamp and over the head stack. It's a tight fit with these metal cable and taping them make it simple to reinstall on the bike. I put the tape right over the top of the piece of tape I was using to mark the Pivot clamp location.

In the picture above you can see the cable are taped in place. Once the boom is on the bike the tape is removed. The tape you see in the following pictures; is my positional marker and it is not holding the wires.

At this point it was just a matter of connecting all the wires. Special care is required to keep the shifter cable tight during installation so that the modified center routing doesn't rub and damage the cables inside the shifters. Going slow was the only real compromise.

The external cable under the brake is a non issue once the bars are wrapped. Notice I have the brake mounted just a little lower than the end of the bar; this is by design and puts one of the power hand positions over the top of the brake and shifter and not under the brake where the wire is. After wrapping with tape there is a nice and comfortable hand grip at the end of the bar with two solid hand positions. No extra padding was needed; just careful figure-8 wrapping of the excellent cork tape that comes stock with the Silvio.

The rest of these photos are side by sides of the bullhorn Silvio next to my wife's Silvio build. Her's is built with Carbon bars; alla Ivan at the top of the this thread. Compared to mine bike, with stock bars, her "on hood" hand position was a full 3 inches lower than mine.

With the bull horns installed My hand position is just over 1 inch lower than hers. Basically I picked up the 60mm drop and a slightly lower rotation angle. The result is a perfect riding position for me; without an extension installed. (A 50mm extension could still be interesting; as I have plenty of clearance to spare for that. 100mm is too much for my body size).

Now I mentioned earlier that; the bars could be just a tag bit longer to get an optimum reach. If Cruzbike wanted to produce a bar with a bullhorn with a 60mm drop like these specifically for the Silvio, they would likely need a custom bar with about 40mm more forward reach; maybe a little more and let the customer shorten if needed.

For me I got lucky and the problem just went away. I have switched the seat pad to Ventisit Vendetta pad, the thin version. The different between that new seat pad and the stock one is about 25-40mm in thickness (hard to say how much the stock one compress). So sitting on the Ventisit my arms are perfectly extended just like all the Vendetta bullhorn photos and drawings.

I must say it's a supremely comfortable position and I can generate a lot power with arms assist on the trainer. I am really glad I did this project, I have the Vendetta like riding position that I was craving with the suspension I needed to tame the chip-seal roads and care for my next injury.

Thank you for the Inspiration Ivan, and sorry about hijacking the thread; I didn't expect it to be such a big project of trial and error.

Oh and as a photo foot note; this a family room trashed by this project

If you do that to your house; you might find that you have to calm the wife by building her one like this:

Or in her case; teach her to build it herself. I did the hack sawing and the derailleur tuning; she did all the rest. I would say that this photo sums up how we both feel about our new Bikes.

 

[ratz]

Modification strenght

AK,

Well that is always the question when modifying anything metal. I will inspect the boom every ride or every 50 miles which every occurs first. My carbon fork failure has taught me to inspect even if you don't mod something.

Obviously my changes are at my own risk. But I have a friend that plays mechanical engineer by day. It was his suggestions:

1) That the opening be before the pivot clamp due to all the weight being on the down side of the clamp
2) The the opening be narrow running in the direction of the boom; versus wider and shorter.

So that's what I have; the opening is 10-11mm wide; the width of two brake housings and the cable come out over-lapped.

I went back an made the corners slightly rounded (not in photos) just to ensure there was no 90 degree edge that would allow the metal to sheer on a existing cut line.

I did some crude flex testing before and after and could not measure a change in stiffness.

If it fails miserably I'll be the first to let people know.

 

[ratz]

Arm position

The wife caught me napping on the bike during test ride time; but it's a good picture of the full arm extension position with the bull horns.

 

[ratz]

Brake routing

Ok so here are the brake details.

First you can see the entry hole where the cable runs into the bars.

Before molding and wrapping the cable looks as follows. These are TRP carbon levers. I love the way they feel in the hand compared to cold aluminum levels. They feel much like the levelers on SRAM Force brifters.

If left bare like that, or wrapped with just bar tape you would get the cable on tendons problem that John worked so hard to avoid. I did try to ride it like that with just wrap and it was sub par.

So I used an old biking trick to fix it.

I bought a roll of black gorilla tape. Gorilla tape is basically super thick duck tape that is much tougher, stiffer than duck tape and it is water (sweat) proof. I cut small strips of the tape which I applied in layers next to and around (not over) the the cable. Basically you use it like papermachete to build up the bar to enclose the cable. It sounds a lot harder and more tedious than it is. All and all it takes about 20 minutes with a good sharp scissors if you go slow. When I was done the cable disappears into a molded bar end completely smooth and shaped to my hand size. Unlike duct tape, as Gorilla tape wrap will not compress when you squeeze it. The I just wrapped with the Stock Silvio cork. Eventually I'll probably redo it with Lizard skin tape. You could also use modeling clay, and any self drying pudy, but then you'd have to wait for it to dry and harden.

Then I wrapped the bar just like and any other bar.

Cable is a standard Road brake cable. Only negative is there is no Pivoting mount; probably will change the brake cable annually because of that. Right now for shake down I'm using non-teflon cables but will swap those out when I'm sure everything is working perfect and no longer tweaking. The housing was loaded with TriFlow and these brakes snap right back into place with the spring assist; there is no hesitation.

Hand position #1 - used when approaching a braking event as the hand preps to operate the brake.

Hand position #2 - Cursing position.

Hand position #3 - Entering/Exiting braking event

Position #4 - downshift and ready to brake.

Sharp bend in the end might be a bit much; but is very handy for going up hill in a sit up position; the bend does not compromise the drop.

Here's a video walk around. Sorry it's cold out so you have to see the messy basement playroom / bike workshop

 

[ratz]

If I was making these for the masses

Eric,

If I could tweak these bars for mainstream. I would do the following:

1. Keep the 60mm drop.
2. Make the width 460mm (these are 440mm) offer in 460, 440 and 420 widths.
3. Increase the forward reach 60mm longer
4. Leave the end of the bars steeply bent. While it looks too extreme when is paired with the 60mm drop it works and keeps the wrist straight. At most rotate it 5 degrees forward
5. Create the brake cable cover as a nice welded on aluminum piece; or supper stiff rubber.

Note for #2: I've been waiting 3 weeks for 460mm version to get here from the UK. I can ride the 440mm just fine, but my thighs get very thick in season; 460mm would allow me to ride sloppy and not get leg interference.

Notes for #3: I compensated for 1/2 of this with my thinner Ventisit seat pad. The Extra 60mm reach would be used to bring the steam clamp closer to the chest area by 20-30mm to give a more leg clearance for cold weather clothing. And it would allow the stock pad to be used and have good straight arms.

Other thoughts you look at the ends of the bars in the hand shots it it very brifter-ish. If you look at Ivan hand positions they are very very similar. Still think there is a option to put brifters on the end of bars like this and have them function as the horns.


Next Actions:

• Need to find someone that with the cad skills to dimension these thoughts up correctly so they could be made.
• Add the 50mm extension we are having made (still waiting on final quote from CNC shop for volume run) and see how they interact.
• Replace the 440 with 460's when they arrive finally
• Hack off the end of the 440s and put brifters on the end prove that out.
• Get a aluminum pipe bender and violate the stock Silvio drop bars into a protype of the this design.

 

[BentBierz]

Hand position #2 - Cursing

Hand position #2 - Cursing position.

Dammit...I need a cursing position!

 

[Eric Winn]

Bob, did you ever look at

Bob, did you ever look at using something like the Jtek levers?

Potential conflict with your thigh when mounted in the typical inboard position. Unfortunately flipping them outboard and doing some of your shifty, er, shifter surgery probably wouldn't work as the levers would not be "under your fingers"...

See:

http://cruzbike.com/bullhorns#comment-20448

[URL='http://cruzbike.com/bullhorns#comment-20448[/URL]

[/URL]

-Eric

 

[Eric Winn]

Larry, I was sorely

Larry, I was sorely tempted...

Perhaps Bob was typing this up after changing out his front wheel.

-Eric

 

[ratz]

Oppps

Yes the the cruising position photo was over looked; and the true photo for cursing position is missing. To achieve cursing position; do as above but extend your social finger straight ahead. Part of me really want to take that photo and post it, but ....

As for the Jtek shifters I did try them. The ones pictured here only work on Shimano shifters and I have SRAM so I had to get the Bar end clamp ons. However it turns out they only come with 19mm clamps. So they don't fit on the bars. I had home the clamps might be removable but they aren't. I did reach out to Jtek as they are just down the street from me but they never responded. Sadly they were more a more responsive company before the son took over the business.

 

[ratz]

Comparisons

I noticed this weekend that the stock handle bars have some similarity in shape and reach to the bullhorns I installed. I did some comparative photos that might be of use to someone trying to decide about bar reach. A clone of these bullhorns could probably be made using the same stock handle bars, but with a slightly different bend geometry. I don't know the value of these photos, but here they are for completeness.

 

[ratz]

Bullriding - aka double chin theater.

So I thought I'd show off how much weight a person can gain in a brutal winter;

Here are three videos from different angle riding the bull horns on the trainer. I left the audio in. When you hear a screech noise; that is the wheel locking up and the free wheel on the trainer slipping on the tire. That was done intentionally to show the power of the brake levers even when braking with just 1 or 2 fingers.

Video 1 Side angle

Video 2 Back Quarter angle

Video 3 Head on (double chin theater)

 

[ak-tux]

Try bridging to accelerate

Nice work ratz! The "quiver" idea really looks cool. Getting the water bottle looks like you are fetching an arrow lol!

I couldn't help but notice that you seem to sit up to put power on the pedals. If you have no known back problems then maybe you should try bridging to accelerate instead of sitting up. By bridging I mean, you grab the handle bars at your most powerful position then you lift your bottom off the seat slightly and you will be "off the saddle" in a way. In this position, only your upper shoulders will make contact with the seat (and probably some part of your head will make contact with the head rest).

This makes the bike "jump". This position is very powerful and can only be sustained for a few seconds or a minute at most if you practice it.

 

[Eric Winn]

I like the looks of the

I like the looks of the slightly inboard hand position where the drop bullhorn drop .

How does that spot feel on the road? A bit twitchy?

Got a set of rollers?

-Eric