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Questions and answers about sports

What causes frames to break at the (rear) dropouts?

5 min read

Asked by: Tanya Nielsen

When the axle bends, it twists the dropout, which can also break. Some other brands of freehubs solve the axle bending problem with a thick oversized axle. This could work with a freewheel hub too, but I am not aware of anyone who makes that kind of hub.

How do you fix a rear dropout?

Quote from video: This is a two pound epoxy which acts like clay you can mold into place. And you need to knead it for about two minutes for the compound to be activated. Before applying it to the surface.

What is a dropout frame?

A bicycle dropout (drop out, frame end, or fork end), is a slot in a frame or fork where the axle of the wheel is attached. On bicycles that do not have a derailleur or other chain tensioning device, rear horizontal dropouts allow adjustment of chain tension, and can accommodate a range of chain lengths or cog sizes.

How do you fix a bent dropout?

Quote from video: Well you use something like a rag you want to put something soft over it and then go at it with something like a adjustable wrench and slowly bend it that way I mean it's not rocket science guys.

What is a rear dropout?

The rear dropout is the portion of the frame where the rear derailleur hanger is attached. The rear dropout is the joining point (the confluence) of the chain stay and the seat stay on the rear portion of the bike frame (see picture below).

What are horizontal dropouts on a bike?

Horizontal dropouts have a longish slot for the rear axle to fit into, which runs more-or-less horizontally along the dropout. They permit the wheel to be placed in various positions front to rear.

How do bottom brackets work?

The bottom bracket on a bicycle connects the crankset (chainset) to the bicycle and allows the crankset to rotate freely. It contains a spindle to which the crankset attaches, and the bearings that allow the spindle and crankset to rotate. The chainrings and pedals attach to the cranks.

Can a bent bike frame be fixed?

A moderately bent steel fork or frame can usually be straightened. A crumpled or cracked fork or frame can sometimes be made rideable with a welded or brazed reinforcement.

How do I know if my rear derailleur hanger is bent?

The most accurate way to check hanger alignment is to do what professional bike mechanics do: use a hanger alignment tool. This tool bolts to the hanger in place of the rear derailleur and allows alignment checks against the rim. This tool also allows you to correct the alignment by rebending the hanger.

Can you roll out a bend in a bike frame?

Quote from video: I can actually feel I get tighter in there like. This. And working on rolling that dent out rolling those high spots out that's tighten a little bit. And rule it tain a little bit.

Why does surly use horizontal dropouts?

Quote from video: Down. This is just a glimpse into surly's world of weird yet functional dropouts.

How do you adjust dropout screws?

Look for the handle near the center of the rear wheel and pull it back so it’s perpendicular to the wheel. Turn the handle counterclockwise to loosen the wheel so you can move it around. Don’t unscrew the handle completely or else the wheel could fall out. Slide the wheel back in the dropouts to tighten the chain.

How do I adjust horizontal dropouts?

Quote from video: These sliders are called horizontal body dropouts and they make axle alignment. Really easy to do this with a geared bike simply put the chain into the large chainring. And the largest. Cog. This is

How do you change bike dropouts?

Quote from video: So and once you have the chain on you simply pull the wheel back. So that it's clear the dropouts and the brakes. And then slide it forward just like so when it nice and easy.

How do you widen dropouts?

Quote from video: Now my preferred method for expanding the red triangle is using a threaded rod with some nuts and washers.

Can you cold set aluminum?

Since the frame is aluminum, DO NOT attempt to “cold set” the dropouts by spreading them wide until they relax to the width you want. This is a technique that can be done with steel but not aluminum.

How do you bend a bike frame back?

Quote from video: And how to correct the alignment through cold setting to check the alignment on the use a tool called a frame alignment gauges from Park Tool it's an F 82.

Can a bent bike frame be repaired?

A moderately bent steel fork or frame can usually be straightened. A crumpled or cracked fork or frame can sometimes be made rideable with a welded or brazed reinforcement.

How do you reinforce a bike frame?

Quote from video: The way I did it is they had my little jar of epoxy. And I used a clean paintbrush put a layer on the frame and layer of epoxy on the frame just to make it sticky and then I took a layer of carbon.