Road Bike Rack Brackets

[macardoso]

Wife and I are leaving in 5 days for a 150 mile ride along the Great Allegany Passage (GAP) Trail from Pittsburg, PA to Cumberland, MD. Never done any overnight cycling so it will be a bit of an experience.

We bought some nice bike bags with fold out panniers to carry whatever we need. They were not cheap but super well built (LINK). They use a dovetail slide on the rack (LINK) to quickly attach and a clip at one end to keep them on. Should make it easy to bring our stuff into the B&Bs that we will be staying at.

Topeak makes some nice stuff and it is well designed to fit most bikes. Install on my wife's hybrid took all of 10 minutes and it is rock solid. However, my bike is weird - really weird.

I bought it at a great price from a family friend who took a bad fall and gave up cycling. It is a '98 triathlon and sprint style bike. Really fun to ride, but not at all designed for touring. I called the company and they basically told me the bike was never designed for a rack. It is missing the threaded eyelets on the rear axle as well as the seatpost. The seat stays (diagonal bars going up from the rear wheel) are extremely low compared to most bikes. Unfortunately these are the common places to mount a rack. Topeak told me their rack would not fit, and a local bike shop laughed me out of the store when I asked for their help in figuring out a rack system.


^Stock internet photo

So out of determination and frustration, I started designing my own system. The rack needs two threaded holes (M5x0.8) at the rear axle and another two somewhere near where the seat stays would meet the seat post on a normal bike. My plan is to create two blocks which clamp to the seat stays right at the rear axle and one which clamps around the carbon fiber seat beam.

Stay tuned for the machining!

-Mike

 

[macardoso]

For the blocks on the seat stays, I designed a pair of 1x1.5x2 aluminum chunks. They will clamp around the bar and compress with (4) 8-32 cap screws. There will be (3) 10-32 threaded holes (I didn't have an M5x0.8 tap) for attaching the rack.

The seat stay beams are not particularly round or consistent in diameter, ranging from 0.589"-0.628" in the area I plan to clamp them. To get around this issue, I designed a neat clamp which inscribes a square with a side length of 0.580" inside a circle with a diameter of 0.64". This means the clamp will always have 4 points of contact on any pipe within those size ranges.

Using an XL 3/8" endmill, I cut the profile to a depth of 1.5" on my CNC.



The chatter left ridges on the inside that turned out to be rather fortuitous as they provide extra grip on the pipe.



Using the CNC with a workstop is really fun for repeat parts. I rarely get to do that.



A second CNC program with 5 tools drilled all the tap drill holes, drilled the clearance holes, and counterbored the cap screws. Adjusting the feedrate on the first run of the program got chips to break and clear easily so the second run was super fast. I was just going to manually do this, but I think it was actually faster to write the program and let the machine do the work - more fun too.



Two done.



Using a 1/16" x 3" slitting saw, the parts were split in half.



You can see from the wear pattern in the clamp that my four points of contact plan worked perfectly. The brackets are extremely rigid.



And a test fit (ignore the messy basement, I was in a hurry)







The one block interferes with the chain in high gear, so using a sharpie I freehand marked out a wedge to be removed from the block. I eyeballed the dimensions using a toolmakers vise to set a compound angle .



Took a few tries to get enough material removed, but here was the final result.







In the 3rd chain ring and 7th gear, the chain just kisses the block. I cannot hear it or feel it when riding so I will call it good for now. Any lower gear and there is plenty of clearance.



Next step will be to make the single block on the seat beam that keeps the rack from tipping over.

-Mike

 

[yendor]

While you have a beautiful bike for Tri-Competition riding.
I think you are going to be very unhappy with it for a 5 day trail ride.
I do a LOT of bike riding.
I average 80-100 miles per week and regularly do charity event rides of 75-100 miles.

Tri-Bikes have a VERY Aggressive geometry to the riding position which is not going to be comfortable on a long days ride and even less so if it is not paved roads.
I would strongly recommend you possibly Rent or Buy a Hybrid with some suspension features (a min of Front Fork Shocks) for any type of trail riding.

But with all that said your machine work and design for the rack looks great.

 

[macardoso]

While you have a beautiful bike for Tri-Competition riding.
I think you are going to be very unhappy with it for a 5 day trail ride.
I do a LOT of bike riding.
I average 80-100 miles per week and regularly do charity event rides of 75-100 miles.

Tri-Bikes have a VERY Aggressive geometry to the riding position which is not going to be comfortable on a long days ride and even less so if it is not paved roads.
I would strongly recommend you possibly Rent or Buy a Hybrid with some suspension features (a min of Front Fork Shocks) for any type of trail riding.

But with all that said your machine work and design for the rack looks great.

Yeah, it is an issue for sure - definitely appreciate the feedback. As weird as it might be, this bike is my daily ride bike and I've gotten pretty used to it. Maybe it is not peak comfort, but I know how to ride it and the issues are known issues. I also have a hybrid, but it has been a long time since I've ridden it and I don't love the idea of starting out on a long trip with a piece of gear that has unknown problems. It is my backup if the add-a-rack does not pan out.

I've done 75mi single day rides on this bike without a problem. The back to back riding days are definitely a concern, but not so much from the bike perspective as the physical exertion. One cool feature is because you are sitting on an unsupported carbon beam, the bike does actually have suspension to it as the beam flexes. It is pretty comfortable to ride. I've also done day ride sections of this trail on this bike and they went well. The sections I have done are fine crushed cinder and the road tires didn't mind that. If the trail gets worse, I have some knobby spare tires to put on.

Our mileage will be 60, 30, 50, 20 for this ride.

Thanks for the feedback! If it was a terrible choice to bring the bike I will let you know and you can get a "I told you so" in

 

[macardoso]

Now you got me looking. Seen plenty of people riding 700x23 on this trail, BUT there is a solid chance of it raining next week which could complicate the matter significantly. My hybrid is a 700x32 which would do better on soft road

 

[Cheeseking]

What keeps the rack and panniers from pivoting fore and aft? Friction or is there a stabilizing member planned to attach to a non-flexing part of the frame? Cool looking bike btw


Sent from my iPhone using Tapatalk

 

[macardoso]

What keeps the rack and panniers from pivoting fore and aft? Friction or is there a stabilizing member planned to attach to a non-flexing part of the frame? Cool looking bike btw


Sent from my iPhone using Tapatalk

Currently nothing. The rack comes with some spring steel straps that would normally attach to the top of the seat stays or seat post. Since I have neither attachment point, They will attach to the seat beam and the flexture in the beam will be taken up by the flexture in the spring straps. This is only needed to keep the rack from pivoting about the eyelets at the rear axle and does not carry weight.

Thanks

 

[SlowDave]

As stated above, the bike is a bit aggressive for touring but people have crossed the county on unicycles. I have done a fair amount of touring over the years and was going to to the Great Divide Mountain Bike route last year but then everything shut down. The two most important factors for distance riding are comfort and dependability. What you can do one day is quite different from what you can do day after day.

For touring you usually want a more upright position on the bike but your daily mileage is rather low so you might be fine on that.

Is the ride going to be a "credit card tour" (staying in hotels and eating in restaurants)? If so you really don't need to carry much, one set riding clothes, one set off the bike clothes, puffy jacket (I done trips without one and greatly regreted it), riding shoes and off the bike shoes, swim suit, toiletries.

For tools, keep it simple, a multi tool, patch kit with tire levers and a pump. Bring a small bottle of chain lube and oil your chain daily.

Most people new to touring carry way too much and regret it. This is supposed to be fun, not the Batan death march.

Hydration is a giant issue. It cannot be over stated. Never pass a water source without topping off your bottles. You need enough to get to your next known source and a bit extra incase of mechanical problems. You don't want to carry too much. I carry a Sawyer mini purifier because I am often riding in the desert and filling up from cattle troughs. On one trip, an off road desert crossing, I missed a water source and rode for 2 days on 2 tall bike bottles. I was in real trouble and had to back track and go off route to a town where I stayed in a motel that the health dept should have shut down decades before. I endured a night of massive cramping. I consider myself very lucky on that one.

Use products like Hammer endurolytes to keep your electrolyes in balance. Bring a few gels along for when you bonk. Bring some Revoverite packets along as taken within a half hour of the end of the ride they will help you recover and be ready for the next day.

Food and hydration are different for each of us. Personally if I don't eat a meal in the first 50 miles I will not be able to eat. Things that are fine at the beginning of a ride are nauseating as the miles roll on. For example, if you are adding powders to your water bottles only do 1 at a time. On one ride I put that fizzy electrolite stuff in both my bottles and at 60 miles I couln't force that *&^% down. Pure water would have been fine.

Your first day looks like the hardest so be careful. You don't want to get any sort of strain or injury that will haunt you the rest of the ride. The first day is always hard as you will have to sort everything out and get used to carrying the load. Since you are travelling with your spouse remember people get cranky when they get tired. It is best to hold your tongue.

On bike bags look at bikepacking bags. I use a couple small Ortlieb panniers. They are designed for use up front but I use them on the rear. I also use an Ortlieb handlebar roll which holds my tent and sleeping bag. "P" straps are good for holding things to frames where you don't have braze ons.

Your bike was designed for a very specific purpose, to carry a light person very fast. You are using it for the other extreme and that worries me a bit. The frame was not designed to carry the loads you are going to carry and where you are going to carry them. If you go light it might work out.

If you have felt any discomfort in your hands riding that bike have the bars double wrapped. Salsa makes a gel tape that works well.

The other contact point you have to worry about is your butt. I assume you are using padded cycling shorts. It is important to get out of them as soon as possible ater the day's ride. Also at least wash that area if you can't take a shower. There are antibacterial liquid soaps that help. There are two type of saddle sores, one from chaffing and boils. Either one will ruin your ride so keep it clean.

I could go on and on because cycle touring is a passion for me. If you have not checked it out yet go look at Crazyguyonabike.com.

Have fun.

 

[mattthemuppet2]

Nice work! I remember those soft ride bikes, there was a lot of inventiveness early on in road bike design.

Rather than triangulating with the soft ride beam/ saddle I would suggest making a bracket that triangulates with the down tube or futher up the seatstays (above the brakes?). That beam is designed to flex to provide a measure of suspension, so if you hit a bump it'll force your panniers backwards. You can potentially have alot of weight high up on a relatively flexible platform so think about that when you design the rest of it. You may be fine in a straight line, but any sharp maneouveres (crazy dog, pothole etc) will have the back of the bike wagging the front around like crazy.

Also try and get the rack as low and far forward as you can get it, while still clearing the tire and your feet. Mudguards wouldn't be a bad idea either as riding in the rain is not much fun, but it's even less fun when you're getting soaked front and rear from road spray.

 

[macardoso]

As stated above, the bike is a bit aggressive for touring but people have crossed the county on unicycles. I have done a fair amount of touring over the years and was going to to the Great Divide Mountain Bike route last year but then everything shut down. The two most important factors for distance riding are comfort and dependability. What you can do one day is quite different from what you can do day after day.

For touring you usually want a more upright position on the bike but your daily mileage is rather low so you might be fine on that.

Is the ride going to be a "credit card tour" (staying in hotels and eating in restaurants)? If so you really don't need to carry much, one set riding clothes, one set off the bike clothes, puffy jacket (I done trips without one and greatly regreted it), riding shoes and off the bike shoes, swim suit, toiletries.

For tools, keep it simple, a multi tool, patch kit with tire levers and a pump. Bring a small bottle of chain lube and oil your chain daily.

Most people new to touring carry way too much and regret it. This is supposed to be fun, not the Batan death march.

Hydration is a giant issue. It cannot be over stated. Never pass a water source without topping off your bottles. You need enough to get to your next known source and a bit extra incase of mechanical problems. You don't want to carry too much. I carry a Sawyer mini purifier because I am often riding in the desert and filling up from cattle troughs. On one trip, an off road desert crossing, I missed a water source and rode for 2 days on 2 tall bike bottles. I was in real trouble and had to back track and go off route to a town where I stayed in a motel that the health dept should have shut down decades before. I endured a night of massive cramping. I consider myself very lucky on that one.

Use products like Hammer endurolytes to keep your electrolyes in balance. Bring a few gels along for when you bonk. Bring some Revoverite packets along as taken within a half hour of the end of the ride they will help you recover and be ready for the next day.

Food and hydration are different for each of us. Personally if I don't eat a meal in the first 50 miles I will not be able to eat. Things that are fine at the beginning of a ride are nauseating as the miles roll on. For example, if you are adding powders to your water bottles only do 1 at a time. On one ride I put that fizzy electrolite stuff in both my bottles and at 60 miles I couln't force that *&^% down. Pure water would have been fine.

Your first day looks like the hardest so be careful. You don't want to get any sort of strain or injury that will haunt you the rest of the ride. The first day is always hard as you will have to sort everything out and get used to carrying the load. Since you are travelling with your spouse remember people get cranky when they get tired. It is best to hold your tongue.

On bike bags look at bikepacking bags. I use a couple small Ortlieb panniers. They are designed for use up front but I use them on the rear. I also use an Ortlieb handlebar roll which holds my tent and sleeping bag. "P" straps are good for holding things to frames where you don't have braze ons.

Your bike was designed for a very specific purpose, to carry a light person very fast. You are using it for the other extreme and that worries me a bit. The frame was not designed to carry the loads you are going to carry and where you are going to carry them. If you go light it might work out.

If you have felt any discomfort in your hands riding that bike have the bars double wrapped. Salsa makes a gel tape that works well.

The other contact point you have to worry about is your butt. I assume you are using padded cycling shorts. It is important to get out of them as soon as possible ater the day's ride. Also at least wash that area if you can't take a shower. There are antibacterial liquid soaps that help. There are two type of saddle sores, one from chaffing and boils. Either one will ruin your ride so keep it clean.

I could go on and on because cycle touring is a passion for me. If you have not checked it out yet go look at Crazyguyonabike.com.

Have fun.

Dave,

Thanks for the reply. This is our first touring trip so it will be B&Bs + restaurants at the towns along the trail. Wife and I have been working a lot on handling mileage better and better. Calorie intake and electrolyte replacement really make all the difference. Our normal rides are 20mi max with as fast a pace as we can do (18-19mph), but we have less experience on the long stuff. I have normal granola bars, Gu gels (just a few), and the electrolyte (no calorie) tablets for water. I will have (5) 22oz water bottles between the two of us.

At the responses here and some more research, I think I'm decided to switch to my hybrid. No suspension, but it does have 32mm tires rather than the 23mm on the bike above. Only bummer is my wife is in much better shape than me and kicks my you know what when I am not on the road bike. Probably less of an issue for this trip.

I do need to re-wrap the tape on the bike and I'll do as you recommended with double wrapping. My hands can get sore after 30 miles.

Here are our packing lists, am I missing anything?





I'll check out that site.

Thanks again everyone! -Mike