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Racks mounting holes

Old 11-02-14, 08:47 PM
  #1  
totops1
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Racks mounting holes

Hi!
I am trying to convert my Specialized Allez Elite 2007 into a commuter to go to work and Ive been looking at where i could mount the rear rack that I bought (Topeak Super Tourist)
I tried this afternoon to remove the screws from the frame (nearby the chainstays) and I found my allen wrench starting damaging them. The screw wont move!
Now i am starting to wondering if those screws are meant to be for the rack! Could I be wrong ? Do you think I can use them to mount my rack ?

Thanks
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Old 11-02-14, 09:13 PM
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Those screws (more properly bolts) appear to fasten the carbon seatstays to the rear dropouts and are definitely not intended for mounting a rack. It's a good thing you didn't remove them. Also, they seem to have Torx recesses, not Allen hexes, which may be why your Allen wrench didn't work.

This bike has no mounting eyelets at all and the only way to fit a rack is to get one that uses the quick release skewer as a lower support or use P-clamps for both top and bottom fastening. Basically this bike was never intended to have a rack and you are going to have to improvise to mount one.
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Old 11-02-14, 09:24 PM
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Return your rack and get an Axiom Streamliner Road DLX. It is designed to mount to the quick release skewer, and is inexpensive and lightweight.

I wouldn't use P clamps on carbon fiber stays. Too much risk of damaging the stays.
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Old 11-02-14, 09:47 PM
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Originally Posted by jyl View Post
Return your rack and get an Axiom Streamliner Road DLX. It is designed to mount to the quick release skewer, and is inexpensive and lightweight.

I wouldn't use P clamps on carbon fiber stays. Too much risk of damaging the stays.
Meh. P-clamps are usually rubber-coated. That, and the minimal load means that a conventional rack should be fine.

I'm morally opposed to racks that mount to the quick-release. What's the point of a quick-release if it won't quickly release?
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Old 11-03-14, 12:13 AM
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Hi totops1,

I recently thought about doing the same thing you are and I second both HillRider and jyl---they know what they're talking about. If you have any doubts, contact Specialized and ask them, yourself. Your bike is not designed for mounting a rack and the screws in your alloy dropouts should not be used for that purpose.

Carbon frames are wonderful (my main road bike is all carbon) but they are engineered to be light and withstand normal forces from the drivetrain and rider. They are not designed for carrying racks and other auxiliary equipment. Tightening a clamp around a carbon tube can fracture it because it is not designed to take pressure in that direction. For example, the Owner's Manual for my carbon Team Fuji road frame not only says to not clamp to the tubes, it also says to not carry the bike with the kind of bike carrier that clamps the top tube (a common kind of carrier). When I need to mount my carbon bike on my repair stand to service the bike, it must be clamped via the seat post.

If bike manufacturers wanted carbon frame tubes to be able to handle clamping forces, they could design them to---it's not difficult (most carbon seat posts are designed for it). But it will add weight to the frame and the primary purpose for making a frame with carbon is to reduce weight. So most carbon frames are designed using the criteria for a race frame---not a touring or commuter frame.

Another example: I have a Ritchey WCS carbon Evolution handlebar on my Fuji road bike. Ritchey engineered it to handle clamping force at only three locations: The center (where the stem and, optionally, aerobars will clamp to it) and on the curves (where the brake/shift levers are clamped). Clamps cannot be used anywhere else without risking a catastrophic failure.

Furthermore, to keep clamping forces to a minimum with carbon frames and components, you should always use a friction compound. It lets you reduce the torque by 1/3 to 1/2 what you would normally need for metal parts. For example, clamps that attach to my carbon handlebar should not exceed 5 Nm and this is easy to accommodate with friction compound like Part Tool SAC-2. (By the way, friction compound works just as good with titanium, aluminum and steel parts.)

The safest place to connect a rack to your carbon bike will be at the axles. To that end, jyl's suggestion to use an Axiom Streamliner Road DLX is a very good one. Here are three more suggestions that you might want to consider. But supporting a rack at the axle is still the best option in my opinion.

1 - Connect a rack to the seat post only. Most seat posts (even carbon ones) are designed to handle clamping forces. The Ibera IB-RA1 is designed to do just that. This option can work if the load you carry isn't too great and sufficient seat post height is available. My wife and I each have an Ibera IB-BA1 bag and love them---it will fit onto this rack.

2 - If the axles and seat post are not viable, another possibility is to use a specialized rack that is designed to mount onto carbon seat stays like the Thule Pack 'n Pedal Tour Rack. It attempts to distribute the weight over a wider section of the seat stays and uses rubber to pad the clamps. But this would be my last choice and I would use care not to put much weight on it.

3 - Another possibility is to use a specialized seat bag. Revelate Designs (Alaska) makes some interesting ones but they appear to be designed more for touring than commuting. The Viscacha bag holds an amazingly large amount of stuff yet attaches only to the seat and seat post.

It's tempting to convert a carbon road bike to a commuter. It can be done if you understand the limitations of your frame and don't exceed them. But the ideal thing to do would be to buy a hybrid bike that has been designed with that purpose in mind from the beginning. Carbon frames are very rare in this new---but growing---segment, but a few do exist and they're equipped with mounts for racks, fenders, the works. If you can find one, the 2014 German-made Ghost Speedline Lector 9000 is a carbon-frame hybrid that leans toward a road bike. But this model was dropped from their 2015 line so you may have to hunt to find one.

Kind regards, RoadLight
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Old 11-03-14, 03:56 AM
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I going through the options for a similiar commuter setup, carbon seatpost, carbon seatstays, and little or no place to secure a rack. From all the good folks that responded to my cry for help in https://www.bikeforums.net/touring/97...-mounting.html, here are a couple other suggestions:

https://Topeak® Cycling Accessories ? Products - RX BeamRack w/Side Frame (E-Type)

https://Arkel Randonneur Rack - Seat ... Post Friendly

Check out the thread for rackless bag and excellent clamp options.
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Old 11-03-14, 06:27 AM
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You Over bought the wrong bike to now want a rack . Now your only choice is to get something you use your axle skewer to hold it up

answer is NO .. the chain stays are batch made the same for all sizes
the angle that the seatstays Meet the dropout is a lower angle as the sizes decrease

so they just use that Bolt connection to save on making a lot of different dropouts. IT was Glued and screwed together before Painting.

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Old 11-03-14, 10:28 AM
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Old 11-03-14, 11:25 AM
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I am not a fan of seatpost mounted racks - I have never seen one that I thought sufficiently resisted turning on the post - but that might be a good solution for this problem. THe 'good' ones like Topeak etc. generally also have bags designed to fit their limited mounting area.
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Old 11-03-14, 01:44 PM
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An Arkel seat-post mounted rack might work.

Arkel Randonneur Rack - Seat Post Rack - Carbon Seat Post Friendly
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Old 11-03-14, 04:49 PM
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Originally Posted by jyl View Post
Return your rack and get an Axiom Streamliner Road DLX. It is designed to mount to the quick release skewer, and is inexpensive and lightweight.

I wouldn't use P clamps on carbon fiber stays. Too much risk of damaging the stays.
I am only quoting this post but I have to say that pretty much all of the others are very useful to me, thank you to all of you.
I admit that this Axiom streamliner is tempting. Like "Jeff Wills" pointed out, it would make me reconsider the meaning of quick release skewer but at the same time, I am not excited to have thick rubber clamps (P-clamps) showing on my bike.
The seat clamped rack...Im not a fan either.

Looks like the Axiom is worth a try for me and its pretty cheap too!

Fietsbob, I am not sure if I over bought my bike. It is my second road bike (my first one was a GMC denali that was way too small for me) and I think that my usage just changed over the last year. However, I bought it used for very cheap so again, I don't know if I over bought it. I would say that at that time I thought that those screws were eyelets due to my poor mechanic skills and I waited a year because I didn't have the budget to buy a rack and some panniers (budget that I have now ;-). Live and learn, at least I didn't do a $2k mistake ;-)

Last edited by totops1; 11-03-14 at 04:52 PM. Reason: ok
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Old 11-03-14, 05:39 PM
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Looks like the chainstays are metallic. If so, then could the D clips be attached to those?
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Old 11-03-14, 05:52 PM
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I worry about crashing, and the bike landing on the pannier and maybe me landing on the bike, and that sideways impact cracking the carbon stay. I'm pretty sure the stay is design for load in one direction but not the other.
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Old 11-03-14, 08:47 PM
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Originally Posted by Gresp15C View Post
Looks like the chainstays are metallic. If so, then could the D clips be attached to those?
Correct, the chainstays are in aluminum whereas the seatstays are in carbon
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Old 11-04-14, 09:38 AM
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If it were me, I'd replace the seatstay to dropout mounting screws (not bolts) with a longer version and use the protrusion as the rack mounting point. These screws are most likely a standard 82* countersink so finding a longer screw is not likely a problem.
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Old 11-04-14, 11:45 AM
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You will need an aluminum seatpost for this but I have one on my commuter bike for several years now no issues with it and have put several pounds in it very sturdy rack.
I have one of these TransIt Seatpost Racks
With this sitting on it TransIt Epic DX Rack Trunk
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