[{"data":1,"prerenderedAt":417},["ShallowReactive",2],{"article-en-hub-spacing":3,"articles-en":321},{"id":4,"title":5,"applies_to":6,"author":9,"body":10,"confidence":299,"description":300,"extension":301,"faq":302,"meta":309,"navigation":310,"path":311,"seo":312,"sources":313,"stem":316,"test_bike":317,"topic":318,"updated":319,"__hash__":320},"content_en\u002Fen\u002Fwissen\u002Fhub-spacing.md","Hub Spacing and Axles for an E-Bike Conversion",[7,8],"front","rear","fabio-gentsch",{"type":11,"value":12,"toc":286},"minimark",[13,17,22,96,106,110,150,153,157,168,171,175,178,192,195,199,207,211,219,223,261,265,273,277,280],[14,15,16],"p",{},"Hub spacing is the distance between the inner faces of the dropouts that hold the wheel. At the rear, 135 mm is the usual value for hub motors, at the front usually 100 mm. If your bike has a different spacing, you need a matching motor, an adapter, or you leave it.",[18,19,21],"h2",{"id":20},"common-dimensions","Common dimensions",[23,24,25,41],"table",{},[26,27,28],"thead",{},[29,30,31,35,38],"tr",{},[32,33,34],"th",{},"Position",[32,36,37],{},"Spacing",[32,39,40],{},"Typical for",[42,43,44,56,66,77,87],"tbody",{},[29,45,46,50,53],{},[47,48,49],"td",{},"Front",[47,51,52],{},"100 mm, quick release",[47,54,55],{},"almost all bikes",[29,57,58,60,63],{},[47,59,49],{},[47,61,62],{},"12 × 100 or 15 × 100\u002F110 (Boost), thru-axle",[47,64,65],{},"MTB, newer bikes",[29,67,68,71,74],{},[47,69,70],{},"Rear",[47,72,73],{},"130 mm",[47,75,76],{},"road bikes, older bikes",[29,78,79,81,84],{},[47,80,70],{},[47,82,83],{},"135 mm",[47,85,86],{},"trekking, MTB with quick release",[29,88,89,91,94],{},[47,90,70],{},[47,92,93],{},"142 or 148 mm, thru-axle",[47,95,65],{},[14,97,98,105],{},[99,100,104],"a",{"href":101,"rel":102},"https:\u002F\u002Ffahrrad-xxl.at\u002Fblog\u002Fe-bike-umbausatz",[103],"nofollow","Fahrrad XXL"," names 135 mm as the standard for most hub motors. Front thru-axle standards generally need special motors; that is an assumption Fabio is still checking.",[18,107,109],{"id":108},"how-to-measure","How to measure",[111,112,113,121,132,138,144],"ol",{},[114,115,116,120],"li",{},[117,118,119],"strong",{},"Remove the wheel."," Without it you can reach the dropouts.",[114,122,123,126,127,131],{},[117,124,125],{},"Measure the gap."," With calipers or a ruler, measure between the ",[128,129,130],"em",{},"inner faces"," of the dropouts, with no axle and no disc brake in the way.",[114,133,134,137],{},[117,135,136],{},"Quick release or thru-axle?"," If the wheel sits with a lever and a thin skewer, it is a quick release. If there is a thick axle with a thread or lever, it is a thru-axle (12 or 15 mm).",[114,139,140,143],{},[117,141,142],{},"Look at the dropout shape."," Open dropouts with a slot or dropouts with a safety tab change how the motor sits.",[114,145,146,149],{},[117,147,148],{},"Write down the values."," Together with a photo and the frame material.",[14,151,152],{},"The hub or axle end sometimes carries a marking such as \"135\", which helps with cross-checking.",[18,154,156],{"id":155},"_130-or-135-mm-spreading","130 or 135 mm: spreading",[14,158,159,160,163,164,167],{},"Does a 135 mm motor go into a 130 mm frame? On ",[117,161,162],{},"steel frames"," 130 mm can often be spread to 135 mm. On ",[117,165,166],{},"aluminium and carbon"," it does not work, because they can crack or break. Even with steel it is an intervention in the frame. Do it with feel and in small steps, or have a workshop do it. The frame maker's warranty is usually gone afterwards.",[14,169,170],{},"The easier alternative: look for a motor in 130 mm if your dealer offers one.",[18,172,174],{"id":173},"axles-and-dropouts","Axles and dropouts",[14,176,177],{},"The axle of a hub motor is flattened, usually 10 mm, sometimes 12 mm. The dropouts must take these flats. If the axle does not fit, there are two ways:",[179,180,181,187],"ul",{},[114,182,183,186],{},[117,184,185],{},"File the dropouts."," On steel this sometimes works, on aluminium forks it is risky.",[114,188,189],{},[117,190,191],{},"Choose a different motor.",[14,193,194],{},"As a rule of thumb: do nothing to a dropout that you cannot undo or check. A cracked dropout can cause a crash.",[18,196,198],{"id":197},"torque-arm","Torque arm",[14,200,201,202,206],{},"With aluminium dropouts and with front motors a torque arm is always sensible. It stops the axle from turning in the dropout. More under ",[99,203,205],{"href":204},"\u002Fen\u002Fknowledge\u002Ftorque-arm","torque arm",".",[18,208,210],{"id":209},"thru-axle-and-disc-brake","Thru-axle and disc brake",[14,212,213,214,218],{},"If you have a thru-axle or a front disc brake, that narrows the choice. For disc brakes the motor needs a matching mount, see ",[99,215,217],{"href":216},"\u002Fen\u002Fknowledge\u002Fbrakes","brakes",". Thru-axle motors exist but are rarer and usually pricier.",[18,220,222],{"id":221},"other-things-to-check","Other things to check",[179,224,225,231,241,251],{},[114,226,227,230],{},[117,228,229],{},"Tyre clearance:"," A hub motor and wide tyres need room in fork and rear triangle.",[114,232,233,236,237,206],{},[117,234,235],{},"Wheel size:"," The rim must match the ETRTO number, see ",[99,238,240],{"href":239},"\u002Fen\u002Fknowledge\u002Fwheel-sizes","wheel sizes",[114,242,243,246,247,206],{},[117,244,245],{},"Gearing:"," At the rear most motors need a derailleur setup, see ",[99,248,250],{"href":249},"\u002Fen\u002Fknowledge\u002Fmotor-types","motor types compared",[114,252,253,256,257,206],{},[117,254,255],{},"Frame material:"," Carbon is not suitable, see ",[99,258,260],{"href":259},"\u002Fen\u002Fknowledge\u002Fframe-and-weight","frame and weight",[18,262,264],{"id":263},"if-it-does-not-fit","If it does not fit",[14,266,267,268,272],{},"If neither spacing nor axle fits, a mid-drive is often the more elegant solution, because it does not touch the wheels at all. It has other hurdles though, see ",[99,269,271],{"href":270},"\u002Fen\u002Fknowledge\u002Fmeasure-bottom-bracket","measure your bottom bracket",". If you find the adjustments cost more than the bike is worth, skip it and buy used.",[18,274,276],{"id":275},"how-reliable-is-this","How reliable is this?",[14,278,279],{},"That 135 mm is standard at the rear for most hub motors comes from one source. The other dimensions, spreading steel frames, axle sizes and the statements on dropouts are experience or assumptions that Fabio is still checking.",[14,281,282],{},[99,283,285],{"href":284},"\u002Fen\u002Fconfigurator","Does a conversion fit your bike?",{"title":287,"searchDepth":288,"depth":288,"links":289},"",2,[290,291,292,293,294,295,296,297,298],{"id":20,"depth":288,"text":21},{"id":108,"depth":288,"text":109},{"id":155,"depth":288,"text":156},{"id":173,"depth":288,"text":174},{"id":197,"depth":288,"text":198},{"id":209,"depth":288,"text":210},{"id":221,"depth":288,"text":222},{"id":263,"depth":288,"text":264},{"id":275,"depth":288,"text":276},"assumption","How to measure hub spacing, quick release versus thru-axle, spreading 130 to 135 mm on steel frames and what to watch with dropouts.","md",[303,306],{"q":304,"a":305},"What rear hub spacing does a hub motor need?","For most hub motors 135 mm is the standard. Older bikes and road bikes often have 130 mm, thru-axle bikes 142 or 148 mm.",{"q":307,"a":308},"Can I spread a frame from 130 to 135 mm?","On steel frames it often works, on aluminium and carbon it does not. It remains an intervention you should only do if you know what you are doing.",{},true,"\u002Fen\u002Fwissen\u002Fhub-spacing",{"title":5,"description":300},[314],{"title":315,"url":101},"Fahrrad XXL: e-bike conversion kit (German)","en\u002Fwissen\u002Fhub-spacing",null,"einbaubreite","2026-11-09","YG6q5nqIVoSC0_xrjILDTGhixgpbcdB4RgxOa58Wjto",[322,329,335,341,347,353,359,365,371,373,380,386,392,399,405,411],{"path":323,"title":324,"description":325,"topic":326,"applies_to":327,"confidence":299,"updated":319,"author":9},"\u002Fen\u002Fwissen\u002Fbattery","E-Bike Battery for a Conversion: Position, Space, Range","Where the battery fits on a converted bike, how to measure the space, what branded cells bring, real-world range and how to dispose of it.","akku",[328],"all",{"path":330,"title":331,"description":332,"topic":333,"applies_to":334,"confidence":299,"updated":319,"author":9},"\u002Fen\u002Fwissen\u002Fbrakes","Brakes for an E-Bike Conversion: What You Need","Rim or disc, cut-off levers and sensors: which brakes are enough for a 250 W pedelec and when an upgrade is needed.","bremsen",[328],{"path":336,"title":337,"description":338,"topic":339,"applies_to":340,"confidence":299,"updated":319,"author":9},"\u002Fen\u002Fwissen\u002Fcoaster-brake","Coaster Brake and E-Bike Conversion: What Works","A coaster brake is the most common deal-breaker. Which motors work, where coaster-brake variants exist and when to leave it.","ruecktrittbremse",[328],{"path":342,"title":343,"description":344,"topic":345,"applies_to":346,"confidence":299,"updated":319,"author":9},"\u002Fen\u002Fwissen\u002Fcommon-problems","Common Problems After an E-Bike Conversion","Axle spinning, broken spokes, motor cutting out, jerky starts, fast chain wear: causes and fixes from everyday conversions.","haeufige-probleme",[328],{"path":348,"title":349,"description":350,"topic":351,"applies_to":352,"confidence":299,"updated":319,"author":9},"\u002Fen\u002Fwissen\u002Fconvert-bike-to-ebike","Convert a Bike to an E-Bike: Overview and Steps","What a conversion costs, which motor fits, what the law says and when you should buy a used e-bike instead. An honest overview from the workshop.","fahrrad-zum-e-bike-umbauen",[328],{"path":354,"title":355,"description":356,"topic":357,"applies_to":358,"confidence":299,"updated":319,"author":9},"\u002Fen\u002Fwissen\u002Fcosts","What Does an E-Bike Conversion Really Cost?","Cost items at a glance: kit EUR 400 to 1,700, brakes, tools, small parts. Plus the comparison with used and new (about EUR 2,500) and the cost calculator.","kosten",[328],{"path":360,"title":361,"description":362,"topic":363,"applies_to":364,"confidence":299,"updated":319,"author":9},"\u002Fen\u002Fwissen\u002Fframe-and-weight","Frame and Weight: Which Bike Suits a Conversion","Steel and aluminium are usually fine, carbon is not. Plus the magnet test, total weight, warranty and the wear parts to replace before converting.","rahmen-und-gewicht",[328],{"path":366,"title":367,"description":368,"topic":369,"applies_to":370,"confidence":299,"updated":319,"author":9},"\u002Fen\u002Fwissen\u002Fglossary","E-Bike Conversion Glossary: Terms Explained","Rated power, volts, watt-hours, newton metres, PAS, torque sensor, Higo and Julet, controller and display: the glossary for e-bike conversions.","begriffe",[328],{"path":311,"title":5,"description":300,"topic":318,"applies_to":372,"confidence":299,"updated":319,"author":9},[7,8],{"path":374,"title":375,"description":376,"topic":377,"applies_to":378,"confidence":299,"updated":319,"author":9},"\u002Fen\u002Fwissen\u002Fmeasure-bottom-bracket","Measure Your Bottom Bracket for a Mid-Drive","How to measure shell width and bore of your bottom bracket and tell BSA 68\u002F73, Pressfit and BB30 apart. Step by step for a mid-drive motor.","tretlager-messen",[379],"mid",{"path":381,"title":382,"description":383,"topic":384,"applies_to":385,"confidence":299,"updated":319,"author":9},"\u002Fen\u002Fwissen\u002Fmid-drive-vs-hub-motor","Mid-Drive or Hub Motor: What Suits You?","Ride feel, hills, gears, installation and cost compared, with a clear guide to when a mid-drive and when a front or rear hub motor makes sense.","mittelmotor-oder-nabenmotor",[379,7,8],{"path":387,"title":388,"description":389,"topic":390,"applies_to":391,"confidence":299,"updated":319,"author":9},"\u002Fen\u002Fwissen\u002Fmotor-types","E-Bike Conversion Motor Types Compared","Front, rear and mid-drive motors, friction rollers and seat-tube motors compared: feel, installation, cost and which bikes suit which.","motorarten",[328],{"path":393,"title":394,"description":395,"topic":396,"applies_to":397,"confidence":398,"updated":319,"author":9},"\u002Fen\u002Fwissen\u002Fpedelec-law","Pedelec Law: 250 W, 25 km\u002Fh and Walking Assist","What a conversion may do legally: 250 W rated power, assist only while pedalling up to 25 km\u002Fh, walking assist up to 6 km\u002Fh and what lies beyond.","pedelec-recht",[328],"source",{"path":400,"title":401,"description":402,"topic":403,"applies_to":404,"confidence":299,"updated":319,"author":9},"\u002Fen\u002Fwissen\u002Ftools","Tools for an E-Bike Conversion: The List","Which tools you need for front, rear and mid-drive conversions and what kits usually lack, above all the lockring tool.","werkzeug",[328],{"path":406,"title":407,"description":408,"topic":409,"applies_to":410,"confidence":299,"updated":319,"author":9},"\u002Fen\u002Fwissen\u002Ftorque-arm","Torque Arm: When You Need One","Why the axle of a hub motor turns in the dropout, when you need a torque arm and how to fit it.","drehmomentstuetze",[7,8],{"path":412,"title":413,"description":414,"topic":415,"applies_to":416,"confidence":299,"updated":319,"author":9},"\u002Fen\u002Fwissen\u002Fwheel-sizes","Wheel Sizes and ETRTO for E-Bike Conversions","Inches are unreliable, ETRTO is not: how to read wheel size off the tyre and avoid the 635\u002F622 and 406\u002F451 traps.","laufradgroessen",[7,8],1794254701542]