Has any any one made a groove tube?? I seen a Ted James design tube forming idea but would love to have the hidden pocket on my top tube like the old vintage GT Bikes… and Internal routing is annoying In my opinion
I am having trouble visualizing this. Do you have any pictures or examples?
Sunday bmx did (maybe still does) this to hide the brake cable under the top tube - same idea as some carbon road bars with a slot the housing sits in so you don’t feel it once the bars are wrapped.
Sunday also does ‘wavy’ downtubes. No idea how they do it but it looks cool!
Columbus did this in the 1979 - 1983 years.
The concept didn’t really find a broad market.
I remember the GT one’s were called “groove tube” but I couldn’t find a picture that showed it very well. The groove was only on the seat tube end of the top tube and came on U brake and cantilever bikes… maybe someone has one laying around or will have better luck picture searching. The tube was fairly oval-shaped.
Since the groove didn’t go the length of the tube it wasn’t likely drawn or rolled in long sections. Forming a groove like that does seem challenging but the GT example is encouraging.
For what it’s worth, I also dislike internal routing
This kinda shows what I’m thinking @Aplombcycles means
@Aplombcycles I think you would need to turn some rollers like he did but with only one groove?
ya maybe GT was smart not going the full length to retain some strength at the head tube?? but the examples that everyone put up is what I was thinking but just more room for gear and brake housing. Tidy looking and you can swap a brake from one bike to another… no bleeding cutting lines yada yada yada… also the braze on wont jab your hand . but is there still a patent on the idea
gorilla gravity has a pocket on there frames with a cover you bolt on … so ya but really a plate cover is not needed
I had one of those frames, that was my least favorite part
was it the cover ?? the dropper post cable seems to go where I wouldn’t want it for sure…
I haven’t made one, but after seeing this idea executed really nicely on the new deviate claymore enduro bike, i’m pretty tempted to try it; i’m imagining ill take a piece of say, 38mm tube, and squish it into an oval/catseye shape, then put two lengths of steel round bar through it, maybe ~12.7mm OD, one on each “side”, and then press a third, smaller one externally, in-between them on the “bottom” to create the divot.
im pretty slow to get to things at the moment, ive just moved workshops overseas, but ill post some pictures when it comes around. there IS a new mountain bike on the list for me…
ive formed lots of tubess, just with a vise, or press using wooden or simple steel forms, and this doesn’t /seem/ unreasonable. im imagining it nukes the tubes strength a fair bit though…
I recall reading somewhere that the reason behind the grooved tubes on the Sunday’s was just for dent resistance. Street/park BMX frames live a hard life.
There is a deep groove under the TT specifically for a brake cable. But yeah the other shallow grooves on the DT and TT are supposedly for dent resistance.
The cover was annoying and brittle, but my biggest annoyance was the dropper cable entering the channel on the left side.
@crowe-molybdenum it might make it weaker… but maybe it will add some stiffness in certain directions?? with your pressing idea i am thinking of a extra heavy idea of welding 3 tubes together to make the pocket for fun…
But a mandrel could be made to fit in the tube and press outside one could be cut on the old bridgeport… or in my case the Rockwell…