Ivy-T progress
The most important bit of progress is that the bike is rideable, and I’ve been commuting on it for a week. It isn’t done, it needs a front rack, stem, and tail light (all will be custom), but rideable is a huge step.
It is a nice compliment to Gifford, pretty much the only bike that I’ve been riding for a year. Gifford is utilitarian, the station wagon of a bicycle fleet. The Ivy-T is much sportier, currently weighing in around 23# with fenders, battery powered lights, and a frame fit pump. If I can keep it near 23# with generator lighting and the front rack I’ll be very happy.
Ivy-T in rideable, but not yet finished, form
The Diacompe GC450 centerpull brakes work very well. They almost never squeal, do a fine job of stopping, and are light and nice looking. I'm surprised, but the 27 year old brake pads (never used) even work well.
Brandon Ives did a nice job brazing the lugs (with silver). My fork crown, done in brass, is a little messier.
Here are some photos showing some of the fork building steps. I don’t have a photograph of the fork raking because I raked these fork blades months ago at Alistair Spence’s shop. I don’t have a fork bending form yet.
First the crown was brazed to the steerer. This is done first so that I can turn the crown race down on my lathe (easier without the fork legs attached).
I remove the flux and clean up the crown by hand. The aluminum rod sticking out is a part of the fender mount, and works with an eye bolt to keep the fender in place. It will be cut trim at installation time.
Dropouts are brazed in and cleaned up. I made these dropouts myself on the CNC mill.
I use this fixture to check the frame angles and set the fork blade length. The fork blades are uncut and the front axle height is setup until the angles are correct. The difference between the front and rear axle height (142mm front, 150mm rear) tells me how much fork blade to remove (8mm in this case).
The fork blades are not yet brazed during this operation. A dummy headset (made by Alistair Spence) is in place.
seat tube angle
head tube angle
The fork and trimmed down blades are set into the fork fixture for brazing. This is my second generation fork fixture, I'm going to sell these as a kit later this winter.
The blades are brazed into the fork crown.
The flux is soaked off in hot water and everything is cleaned up. The top hole on the inside of the fork crown is open as a vent hole and will be used to run the wire for the front light.
The fork alignment is checked on my alignment table. I had to tweak one fork blade slightly. Rake was left at 63mm.
Finally, here is a photo of the fender mount in use. I learned about this setup from Jan Heine. The fork crown is drilled in the back, and there is a blind hole in the front. A piece of aluminum rod (fender stay) is put into place. The tension of the fender’s eyebolt holds it in place. It looks very clean, it is light, and it was easier than making a threaded fitting in the bottom of the fork crown.
Cool Alex :^)
It has been a lot of fun watching you become proficient with the rack and frame building. A couple questions… What happened to the original Ivy bike that (I think) you modeled Gifford after, bare frame hanging on a peg somewhere? Also, for the rod through the fork crown, are those the normal brake bolt holes or something smaller? Will a normal 700C fender install leave any pieces long enough to do this?
Thanks, Doug
My old IvyCycles was a victim of a car/bike accident. I actually got hit by the car almost immediately after taking delivery of the frame. That put a small stress fracture at the bottom of the downtube just behind the headtube lug that wasn”t noticed during inspection. Two years later the fracture had grown to go around the circumference of the downtube. The frame now lives with John Speare, who had a replacement downtube brazed in and used it for some testing to design his own custom frame.
The Velo-Orange fenders come with long stays that are more than long enough in 700C to leave the little bit necessary for that fender mount. A regular fork crown through hole is 6mm and the stay is 5mm, but it should work anyway. You could also get a 6mm rod of suitable length from a hardware store by purchasing a very long 6mm stainless bolt and cutting off the head and threaded section.
oh a fork fixture kit, very exciting!
Nice. I like that Gifford is sort of sui generis and this bike has more of a classical appearance.
Alex, if you remove 8mm from the fork legs, won”t that change the frame’’s angles slightly? The front axle height adjustment on your jig isn”t parallel to the head tube….
8mm at 73 degrees has a 7.65mm vertical component. I”m going to call that close enough, especially since my cut was probably not to within a half mm.
It’’s a lot better than assuming that the frame was built exactly to spec and just doing the fork based on the drawing as well. The front end geometry is pretty important to me, so I like having this checkpoint along the way.
That fixture gets a lot of use in my shop, I also use it when building porteur racks to support the platform.
Great to see the progress on this. How does the gearing on the gifford compare to this, I admit that with a 44/30 double I expected to see more of a “road” range cassette?
What kind of rack will you be building for this -and where will it mount? Just curious as your front fender crown mount seems to take the location of a typical Wetmore front rack mount. Also, the rear fender stays have a nice symmetric dogleg to them. Aesthetic or is there some other purpose?
Good set of questions Jimmy.
The cassette will likely be replaced with an 11-28 or 11-30 or something smaller. I used the 11-34 because I had it and wanted to get the bike on the road. I have to admit that the 34 has come in helpful a few times when I”ve been pulling my trailer up steep hills, and I kind of like riding around without dropping out of the 44 on normal hills.
The rack will be a smaller handlebar bag rack. It will either mount to the brake studs and mid-fork locations, or to the fork crown and mid-fork locations. I”m still pondering many options with the rack. The biggest one is internal light wiring and using 5/16″ x 0.028 tubing, or exposed wiring and 1/4″ x 0.028. The 1/4″ tubing looks a bit nicer for a handlebar bag rack and also weighs about 50 grams less for a rack of this size.
My employer’’s bike shuttle uses the normal bus rack, but adds a second rear wheel hook that sits on the fender. It hits normal fender stays, so the S-bend fender stays are designed to clear that hook.
Nice work, Alex. If you can keep the weight at around 23lbs fully equipped that would be among the lightest rando bikes BQ has tested. I think the full carbon Crumpton was around 22lbs. Very impressive. I think you mentioned 8/5 tubing at some point? The front fender attachment at the fork crown is smart. I always though an eyebolt hanging from a nutted bolt (for brakes that don”t have a through bolt) seemed like cludge.
BQ tests with a Brooks saddle though, I”m running a plastic one that saves a bit of weight.
We”ll see. The rack and dynohub will add some weight, but some other changes that I”m making (new stem, handlebars, brake levers) should lose some. The wheels are the primary place where I could save real weight, but I”m unlikely to build a new set. Maybe a front one to run a sonDelux instead of my old SON27.
The frame tubing is 8/5/8 steel (Kaisei 019). Fork blades are True Temper, with a special ultra-light Pacenti steerer. The pump is an ultralight Zefal that Jan gave me.
23lbs will be great, 24lbs (including pump) is probably a realistic target.
Alex, are you happy with that WTB saddle for long distance rides? I know you”ve been a fan of the Brooks B17 for a long time (as have I). The Son20R or sonDelux is a pretty good weight savings over the son28. As a bonus it seems to transmit less vibration than the older, higher output dynohubs. Even 24lbs is great considering you haven”t gone to any “stupid light” componentry. What brake levers are lighter than the Shimano aero levers? I know the Campy carbon ones are light (and crazy expensive) and also some older less ergonomic levers might save weight. Perhaps the SRAM levers? BTW I switched out the XTR triple front derailleur on my rando bike that is equipped with a compact double for an older Suntour Cyclone. It shifts a little better and the flat cage does not rub on the inside of the crank arm (a Ritchey 110bcd with a Q factor around 140mm).
For rides up to 20 miles this saddle has been fine. I haven”t done a ride longer than that yet. It will probably be a couple of months before I can take this bike on a 60-100 mile ride and really see how it does.
The vibration is the main win on the sonDelux for me, and the primary reason for me to upgrade. The half-pound weight savings are a nice bonus though. I have a perfectly fine SON28 in a 700C rim, so I just need to decide if it is worth buying a new hub and building up a wheel for. If I do go down that route I”ll probably use a lighter rim too (the CR18 is a great rim, but not light).
I”m getting a pair of the Campy carbon brake levers from a friend for a good price. That”ll be the only carbon bike component that I own. I do have a carbon fiber kayak paddle.
The front derailleur is going soon, I just haven”t dug through my pile to find a replacement. It doesn”t do well at all on this bike. It is my favorite triple front derailleur, but it doesn”t do well with low Q doubles.
I just did some quick math, and it looks like a front wheel with 28 1.8/1.6 spokes, sonDelux, and Velocity A23 rim would be the same weight as my current front wheel with 36 2.01.8 spokes, XT hub, CR18 rim. My SON28/CR18/36 spoke wheel is a pound heavier. That makes the SONdelux quite compelling.
Switching to the Campy carbon levers and Nitto Soba bar saves me 80 grams total, which gets me half of a front rack. The new stem and cutting off the steerer should get me the other half.
Build a new rear wheel (figuring I can drop 100 grams on the rim, and 75 in spokes+hub) and I”m probably still around 23lbs. That is probably not worth it.
When I take the bike apart for painting I”ll measure each component instead of going based on internet weights.
I know you went with the new A23 rims. I am interested in your thoughts on them once you have a chance to get some miles. Did you use things like Al chainring bolts to save grams? I would think they would be adequately reliable (as long as they are greased as they can seize otherwise). I was reading an old Rivendell catalogue (of all things) and they suggested Ti crank bolts as an innocuous place to save weight.