I just tacked on the steering head tube to the fishmouthed front end tubing at the required 67 degree angle to see what would happen, and the font wheel wants to flop to one side. I have never ridden a Timberwolf trike before, so I don't know if that will work itself out later? I went ahead and changed the angle to 70 degrees and it still was flopping, but possibly without quite as much of a droop now. I'm hoping that 70 degrees will be enough to stop that annoying habit? Of course there is no weight on the trike as yet, so maybe I'm worrying about nothing??? Any delta trike builders out there want to comment? Thanks for your input!
Timberwolf Head tube angle- / "Wheel Flop?
- Thread starter Tillerman6
- Start date
That sounds a bit odd. My delta is also in the 67 degree range with no wheel flop at all. Maybe post up a picture. There may be a slight chance of an error in checking the angle.
I built a couple timber wolf deltas, with the 67 degree head tube angle. They ride fine, but they won't track straight if you take your hands off the steering. Is that what you mean by "flop"?
Steve C and Hugh-
Yes- Hugh I want mine to track straight ahead unless I steer it somewhere else! I'm not a bike engineer, but I did have a two wheeler racing bike many years ago with a 72 degree head tube angle and it had neutral but very lively handling. So in the meantime for the Timberwolf- instead of the 67 degrees called for in the plans- I welded in a 70 degree angle as measured with a digital angle finder - (This is 72 degrees relative to the backbone) where the backbone is supposed to be parallel to the ground. I'm hoping that this will be enough to get rid of some of that "wheel flop"
I also have another delta trike - designed it and built from scratch- It uses 700 C wheels all around and handles almost perfectly. The front wheel will flop if the trike is standing still or when rolling backwards, but you cannot feel much tendency to turn while riding in a straight line.
I do not wish to say that there is anything wrong with the 67 degree angle in the plans, and my change may have actually made things worse, but I was wanting to get some input from some other builders and see what they think. It should be fairly easy to change the head tube angle by cutting a wedge out of the underside of the tubing only ( do not cut it completely - but leave the top face of the tubing intact!!!)
I should probably just copy that head tube angle and re-cut my Timberwolf frame to match- This is not as much trouble as you would think with the square tubing,
Yes- Hugh I want mine to track straight ahead unless I steer it somewhere else! I'm not a bike engineer, but I did have a two wheeler racing bike many years ago with a 72 degree head tube angle and it had neutral but very lively handling. So in the meantime for the Timberwolf- instead of the 67 degrees called for in the plans- I welded in a 70 degree angle as measured with a digital angle finder - (This is 72 degrees relative to the backbone) where the backbone is supposed to be parallel to the ground. I'm hoping that this will be enough to get rid of some of that "wheel flop"
I also have another delta trike - designed it and built from scratch- It uses 700 C wheels all around and handles almost perfectly. The front wheel will flop if the trike is standing still or when rolling backwards, but you cannot feel much tendency to turn while riding in a straight line.
I do not wish to say that there is anything wrong with the 67 degree angle in the plans, and my change may have actually made things worse, but I was wanting to get some input from some other builders and see what they think. It should be fairly easy to change the head tube angle by cutting a wedge out of the underside of the tubing only ( do not cut it completely - but leave the top face of the tubing intact!!!)
I should probably just copy that head tube angle and re-cut my Timberwolf frame to match- This is not as much trouble as you would think with the square tubing,
Yes- the steering wants to go hard over if you release the handlebars. Pretty annoying on my original delta design. I eventually got it so it will track straight if the road is not slanted to one side or the other but I don't know what the head tube angle is for sure- That trike is in my remote storage shed right now and I will have to retrieve it and check the head tube angle again.
I think some time back there was a thread on this very topic. I think one of the participants was talking about his delta trike having excessive wheel flop but I don't remember much more than that. It might have been on Bentrider and not on here at all.
Question for you- Did you leave the overall axle length in the rear at the full 36"? I can't find anywhere in the plans that they say to cut it down shorter!
Hugh- I'm using a 20inch front fork and wheel from a kid's bike and the fork puts the front axle about 2-3 inches ahead of the head tube axis of rotation. I have not ridden it yet- hopefully that will happen soon. I just noticed that the front wheel wanted to flop left or right just sitting there, and it reminded me of the problems I had with my original Delta trike design (all 700C wheels and a totally round tube frame) So I wanted to head off that sort of thing before It became a problem. And I don't know if changing the head tube angle just 3 degrees is going to work or not, but I am pretty sure that it is a step in the right direction. My racing street bike from years ago had a 72 degree head tube angle and was very responsive yet easy to ride, so I took a chance and welded the Timberwolf at 70 degrees as referenced to the backbone.
It may not be enough or it might be too much, but I like to experiment and make improvements whenever I can or feel like they are needed.
It might be that your front fork is different than mine which could change the trail? Maybe you have pics of your creation posted somewhere? I had a very hard time a few months ago trying to post pictures on here for some reason. The pics had to be posted to a third party website and then I had to copy the link from them into my messages on here- quite a hassle.!
By the way- I'm also trying to decide on a final number for the overall width of the two rear wheels for the Timberwolf. What did you end up making yours overall? I know the original axle was 36" long and on mine it still is 36" but that seems a bit wide for some situations on the bike trail and maybe for the stiffness of the material if my wife is a bit over 200 pounds. Have you had any trouble with yours in that regard?
My axle situation is still in limbo as nothing is welded as of this posting, but I would like to get some impressions of other builders and decide one way or another as soon as possible.
Also- if you read some of the other comments in this thread- it seems that you are the exception if you have no wheel flop at all and you built your head tube to the 67 Degree angle as per the plans.
There is a picture of my delta under the topic of delta suspension question. The rear axle used on mine is a 5/8" steel with a slot machined into it for some key stock. On many of the bike paths in my city the distance between posts meant to keep cars etc out is 36" So the rear track width is approx 32" on mine.
My delta is 8' long and uses underseat steering with a long rod from the handlebars to the front fork, it may be that the friction in the overall system minimizes any wheel flop. But really when the trike is just sitting there is no tendency for any flop. Also when I roll it backwards out of the garage it tracks straight. Riding it I can just rest my hands on top of the bar's. Bike paths are flat, some roads have a bit of a crown, those require some pressure on the bars. It's going to be a nice balmy 6 degrees C today so when I head out I will double check the head angle and post it up, also take an accurate rear wheelbase measurement.
My delta is 8' long and uses underseat steering with a long rod from the handlebars to the front fork, it may be that the friction in the overall system minimizes any wheel flop. But really when the trike is just sitting there is no tendency for any flop. Also when I roll it backwards out of the garage it tracks straight. Riding it I can just rest my hands on top of the bar's. Bike paths are flat, some roads have a bit of a crown, those require some pressure on the bars. It's going to be a nice balmy 6 degrees C today so when I head out I will double check the head angle and post it up, also take an accurate rear wheelbase measurement.
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The Timber Wolf uses a two piece axil. The total width comes to about 32 inches. The rear weldment is 24 inches wide.
Wheel flop is nothing to do with head tube angle and everything to do with trail.
This is a combination of the head tube angle AND the axle off set from a line running through the centre of the head tube and is usually measured in inches/centimeters.
As with all things bicycle Brad has it covered Rake and trail
Once the front fork is connected to the handle bars the brake & gear cables tend to resist the wheel flopping about 2 much.
As a rule deltas with one drive wheel [ at the back ] cannot be ridden hands off very far as the trike describes a gentle arc away from the drive wheel.
YMMV
Paul
This is a combination of the head tube angle AND the axle off set from a line running through the centre of the head tube and is usually measured in inches/centimeters.
As with all things bicycle Brad has it covered Rake and trail
Once the front fork is connected to the handle bars the brake & gear cables tend to resist the wheel flopping about 2 much.
As a rule deltas with one drive wheel [ at the back ] cannot be ridden hands off very far as the trike describes a gentle arc away from the drive wheel.
YMMV
Paul
As promised I did measure the angle. On mine it's 70 degrees. Also in order to get a little more ground clearance I'm running a 20" front wheel in a 24" fork. And the width at the rear from fender to fender outside edge is 29". The outside edge of the tires using 20 by 1.35" rubber is 28 1/4"
Hugh-
Thanks for getting those measurements! But if your hubs are a standard 4" wide and your frame is 24" wide that makes the overall width 32" at least - I'm at the point where I need to cut the axle length down to it's final length . I guess the fenders are a little inside the center of the outer portion of the hub anyway right?
Hugh- Thanks again for the information. I don't know if it was shown in the plans, but I did not see it anywhere. I guess it's safer to have the axles as short as possible to keep the bending and chances of the wheels hitting something on the trail.
I ended up cuttting the axles down and putting a 3/16" spacer against the bearing side of each hub so it is barely more than the absolute minimum and no chance of the spokes rubbing on the frame.
I'm very happy to have your help on this and your input is most definitely appreciated!
My next question is about the disk brake- I have not welded the disk that holds the brake disk to the axle yet, and that will be the next move I think. I need to make a bracket that holds the brake caliper on to the frame, and of course the alignment of all those parts is somewhat critical if you don't want a wobble- ing brake disk that could rub or squeak when moving.
My bike shop gave me a small bracket that was for mounting a disk caliper to a leg of the front or rear fork of a regular bike, but It is probably not of much use for this application as the gap between the caliper and the rear frame is still several inches.
By the way - I probably won't get much done on the Trike for a couple of days as I'm modifying my welding cart to take an additonal gas cylinder for Argon. This is necessary if you want to do any Tig welding and I already bought the cylinder and the welder is on it's way to me in a couple of days- wish me luck!
Very good to have information! I don't really have much hope of changing the trail as my forks are taken from an existing kids 20" bike.Wheel flop is nothing to do with head tube angle and everything to do with trail.
This is a combination of the head tube angle AND the axle off set from a line running through the centre of the head tube and is usually measured in inches/centimeters.
As with all things bicycle Brad has it covered Rake and trail
Once the front fork is connected to the handle bars the brake & gear cables tend to resist the wheel flopping about 2 much.
As a rule deltas with one drive wheel [ at the back ] cannot be ridden hands off very far as the trike describes a gentle arc away from the drive wheel.
YMMV
But I did take a small liberty with the head tube angle in hopes that it would in some small way help with wheel flop. I doubt that 3 degrees are going to make much difference, but I figured it could not hurt things too much. So this try has a 70 degree head tube instead of 67 degrees as per the plans.
I have another Delta trike that I built from scratch which is fairly stable as far as wheel flop. Right now I'm not sure what the head tube angle is on that one, but I think it's more like 72 degrees. It has a one piece rear axle with dual rear drive clutches in each hub, so it's sort of a no compromise machine in that regard- could be that is why I'm spoiled! LOL!
It may not even be a factor like you mentioned, but I did not feel comfortable with the 67 degree angle after it flopped over just sitting there with just the tack welds holding it together on the garage floor.
I'm glad yours is behaving itself to your liking
Actually the width of the trike is 29" at it's widest point at the rear wheel area. That gives plenty of room to fit through any bike bike bollards which are spaced at 36" here. What I use to make brackets for a disc brake mount is coroplast. I cut it in a shape to fit around the caliper body then use a hole punch to make the 2 mounting holes. Then mount the caliper body to the piece of coro. At approx 4mm it is stiff enough to make a fairly rigid mount. Then using eyesight and a marker trim the coro to a reasonable fit on the chainstay. Copy that to a suitable piece of metal. It will prob need a little grinder work for the final fit.
Once I'm satisfied with the shape and fit the caliper body gets mounted on the bracket. The whole assembly is then slipped over the disc with the bracket resting on the frame. I use a piece of wire to clamp the caliper to the disc then tack it to the frame.
Once I'm satisfied with the shape and fit the caliper body gets mounted on the bracket. The whole assembly is then slipped over the disc with the bracket resting on the frame. I use a piece of wire to clamp the caliper to the disc then tack it to the frame.